Algoflash here in Europe is selling an osmocote slow release type fertilizer (it calls 'basacote') that it says is good, for among other trees, japanese maples in pots (+ other hedges, shrubs). It's 16-8-12 + Mg + S + minors, but it is active over 8-9 months, not 6. This would work from March to November, then. (The temperatures in the warm months where I am are usually not as extreme as in the States, so there could be less of a chance of fertilizer burn.) Is an 8-9 months formula ok or should I only place a slow release fertilizer once the maples start showing leaves, and use a 6 months formula that goes to October? (I could also of course simply remove the cubes come October...). Any thoughts, advice or experiences shared would be welcome.
Schusch--I've been pleased with 8-9 month release here in S.W. Canada. I would apply it anytime now, personally, as it will begin to release with warmer temps and be mostly released by late summer...the rate of ferts. dropping off quite a bit toward fall even tho it's not the end of the 9 months. It just saves me having to make an additional topdress anytime thru the rest of the year. Two things I think are worth noting. Mg is usually magnesium sulphate, and not slow release. It won't last all summer, (even from dolomite it would be exhausted by about August, and the sulphate will go even faster) so you usually can use another shot of epsom salts around then...magnesium oxide is actually best (much slower release) but harder to find. And minors are usually not complete, nor the best balance, in the control release. It's true they would be better than nothing, but they are not perfect in any blend I've seen. I prefer no micros in the control release for that reason. Personally, I like Micromax as the micro source, but whatever, be aware the micros in the control release can create problems with balance (best ratios, like iron:manganese) and overdoses (boron can be bad for this) if you also add any other micronutrient mix that is meant to supply everything just by itself.
growest - thanks for the input and the warning regarding the micros, and the magnesium. I haven't found a source of micros alone here yet (nor osmocote without the micros) - I have read about Micromax in these forums, as well as in Whitcomb's books. I might organize some for next year from the US. As regards putting them in now, it's still freezing at night, plus I'll repot some in a few weeks, so I'll wait until then. Thanks again.
You have to be carefull using osmocote on maples and other woodies because it is a temp. release. On hot days the fertilizer prills can release to much and burn the plants. I like to use a 5-6 month release for plants in containers and a 8-9 for plants in the ground. When growing in containers you want the fertilizer to release when the plant needs it most and will use it. If the plant is done growing and the fert is still releasing it will cause salt build up along with other issues. I have been happy with Apex fertilizer, it is slower relaese, but much more constent.
Yweride, What form of the APEX do you use. OBC Northwest has the 20-10-10 Evergreen (1% Ca, 0.25% Fe, 2% S) 14-14-14 Bloom 21-5-6 Super Iron Topdress (2.2% ca, 6% Fe, 2.6% S) APEX also makes a larger number of other formulations that do not seem to be readily available. Do you know of any other sources in Oregon? As for the extended formulation question, I think the shorter duration fertilizer is the better choice if one was to apply one. The plants can use a good dose of fertilizer before the hot season here to pull them through, but it is quite detrimental in the hottest months if salts build up in the soil. It is important to wait for the plant to be old enough to handle the extended release products and to flush the soil periodically. In cooler climates, these extended release products can be a better choice, or when used in combination with enviornmental controls on younger plants like shade cloth and drip systems. I would recommend using less at first on a control group of plants as not to adversely effect all of your plants.
Thanks for the input, Yweride and mjh - I was planning on using less than the product maker recommends, may be half, for the first year. (The maples are either 2 years old, or 5-7. What would the latter be old enough?) Would that address your concerns, or is the salt build up you mention also a result of the longer period - 8 to 9 versus 5-6 months? Both Algoflash and Fertiligene (another product readily available here) recommend the 8-9 formula for shrubs and hedges, and a 5-6 month formula (15-10-12) for what they call 'green plants' (as opposed to another with flowers). I think the 8-9 months has the added S component. What impact do these different formulas make? As regards temperatures here: any sun we see is positive, also for plants ... MJH- can you say more about the environmental controls you mention? What is shade cloth, and what are the advantages of a drip system as regards fertilization? Thanks.
I think the 5-7 year old plants are a good age. I usually deal with container size, my feeling being that if I am growing plants out in the open here that 5-7gal containers are the smallest that I will want to put extended release fertilizers on. This instinctively has to deal with surface area and root and soil volume. Thus larger plants can withstand some of the salt build up and more effectively use the nutrients. Now, you are in a different situation being in a much cooler climate. What I meant about environmental controls is that a grower or nursery might be able to get away with forcing growth with fertilizers by using a regular watering program (drip, sprinklers, etc) and growing plants protected under a shade cloth. This creates more optimal growing conditions and allows the plant to respond positively to the added fertilizers. Now compare that to my growing practice here in southern Oregon where I push the plants. We grow them in the open with minimal shade and exposure to hot dry sun and winds. We will see weeks over 100 degrees and a longer growing season than many places. In these conditions, maples can become stressed in the mid to late summer months and we would rather not have the excess fertilizer around and the chance for salt build up that will harm the roots. We can get away with it on larger plants, but smaller ones will rebel. So, my point was that I would have to alter the growing conditions of my smaller plants if I was going to apply slow-release fertilizers, otherwise they would fry. Your 5-6 month formula (15-10-12) sounds very good. I would be excited to find that mix. It is nice to have micro and macro nurtients added, but I can see where doing that separately would be of benefit. For me, a complete formula would be easier and save time--so I would sacrifice the ideal mix for efficiency. I always hope to find Sulfer, Calcium and Iron, and with that mix is usually Mg, Mn etc. The combinations of nutrients facillitate eachothers uptake is the main point and while many soils and soil mixes have these nutrients (if we were to test them) they are not always available to the plant. I usually look for the mix with the most calcium, most extended realease products don't seems to have much over 2%, but some immediate release products can have up to 6%. Using an immediate release product is a good option after the first flush of growth if one dose not use extended release products. Look for a low to moderate N component and 7-12 on the P and K are fine. Like I said, the 15-10-12 seems fine.
Thanks, mjh - I'll look at the info on the packages, and compare with your info. If I understand correctly the 8-9 months does not release its content differently from the shorter time version. It is a matter of when these nutrients should be applied. Could I not use the longer version and apply when I want and take out the cubes in the fall - would this not give me more latitude and control? (The companies also use slightly different formulas - as I said in the previous reply - this way I could use the best formula independently of the time span?) I read about applying the spring fertilizer when the maples leaf out, but does this also apply to long release fertilizers, since they are released when it gets warmer? Thanks again.
Coming from a nurseryman's view that has seen how many Maples have died due to timed released fertilizers, not solely due to the fertilizer but more so as to how much and how the capsules were applied, let me point out that even a half strength application of a 18% timed released Nitrogen will be like playing Russian Roulette with your Maples. People can get by using this amount on potted Dogwoods, Pines and other plants but Maples, Camellias, Azaleas and even to some extent deciduous Magnolia roots are too sensitive to have timed release fertilizers applied at less than 3 years of age. Go ahead and use them, not water them in well to disperse the capsules in the potting medium, wait for a real hot day or two and watch what will happen. I've seen it happen all too often to other people. Wait until the plants are about 5 years old to use the timed release fertilizers. A good time is when we bump up a one gallon sized plant into a five gallon. We can lightly sprinkle the timed released fertilizers in with the potting soil, mix in by hand and then pot up the plant if need be but do not and I repeat do not sprinkle a handful of the timed released fertilizer and apply it at the base of the tree and hope that deep or rapid hose watering will disperse the capsules around in the pot for you. The lazy man's way of applying these fertilizers has caused many plant deaths by doing things this way. It is not the manufacturers fault that we lost the plants, we lost them due to us! If you want advice then tell us more about your set up. How do you water your trees? Are your trees grown outdoors year round or grown in containers outdoors for part of the year and then placed in a greenhouse for the cold Winter months? What is your soil medium and how much soil versus potting soil are you using in your mixes? You want help to choose either a 6-month timed release or an 8-9 month. In order to provide decent advice you need to tell us what you really want from your plants and how you are currently growing them. Jim
I would second Jim's advice as it is a more direct to say what I was hinting at. Details about your growing conditions and practices would be helpful. In regards to the application of a spring fertilizer of the immediate release type, that is one method that you can have success with and it carries a much lower risk if done conservatively. Ideal for young or tender plants, also good for areas with short growing seasons as extended release ferts can cuase growth too late in the season. Even with our extended growing season, if I push growth too late in the year, I will often find it a magnet for disease and dieback. I found this out last year while adding liquid nitrogen in my waterings too late in the year. When using the spring application method, I prefer to time the application after the first flush of growth is well underway and the the root temperatures are up in the 60's. If we are talking about pots, that will mean that we need daytime temps in the mid to upper 60's which will happen regularly in May. By may our first flush of growth will be nearly finished. When the plant puts out its first leaves of the spring, it does not need exogenous nitrogen to accomplish this. Root growth is at a minimum and the plant is working off stored energy. To add fertilizers at this time places unnecessary stress on the root system. Also, make sure that you pick up on what Jim said about the 5 year mark and the move from a 1gal to a 5gal. With maples, especially the small plants we see today, it will take that long to get a solid one gallon root system. If you prematurely move maples into larger pots, you may find that they are unable to overcome the excess soil volume that will stay too wet. Wet feet and excess fertilizer are a deathwish for maples. Give them time to get some roots on them. The first 3-5 years in a one gallon pot is not the time we want to see fast and excess top growth. We want to know the root system is developing under them. When that is solid, we can focus on the top growth. To shift this focus permaturely, is to risk the health of the plant. I have been finding that plants I put in 3gal cans a year ago are not happy at all. One is a soil mix issue, but the other is that they did not have the roots on them to tolerate the soil volume. Asking the maple to extend its roots into an area that is staying too wet is losing battle, it just won't happen. Many of these plants are now going back to one gallons as I did not understand what they needed. Knowing what soil mix to use, how to water and what pot size and cultural conditions the maples needs should preceed the urge to fertilize the plants. Maples will do fine if we do not fertilize them as they can grow in a low nurtrient environment. Simply adding some 0-10-10 for the first few year twice yearly may be enough to help the plant along and become strong.
Thanks very much, Mr. Shep and MJH, for the generous offer to help. Let me be more precise: I have in containers about 10 2 or 3 year old grafts - which I got from Esveld (and which were grown ecologically, as they state on their site - http://www.esveld.nl/eme.html) - most of them this fall. They are still in their initial 1 gallon containers. The others are 5-7 year old of which I got this year, some a couple of years ago - from Mr. Choteau in Belgium, who is a serious and dedicated grower. The older ones came in 5 gallon containers, and needed bigger containers, judging from their rootballs. I put them in bigger wooden containers of various sizes 10 gallons and up. I'll be repotting all of them with a new mix, based mainly on pine bark, perlite or clay pellets or grit, and will add some loam, especially the older ones (to give myself some leeway come summer, if a day or two is missed.) I am aiming for a 3-1-1 mix, as MJH suggested in a previous thread for the older ones, and mainly pine bark and perlite for the younger ones. I water by hand, every 3-4 days. I try to use as much as possible rain water, which I collect, for the containers. The climate here is different than in the States (I lived 10 years on the East Coast): less sun, above all, may be a couple or three weeks of really hot temperatures, otherwise rain and grey very much possible, if we are unlucky, depending on the year. The maples get morning sun until 1300, except two that get afternoon sun, but no leaf burn until now. The maples are grown outdoors. I have access to various fertilizers: the slow release 9 month 16-8-12+MgO+SO3+minors I mentioned, the 6 month 15-10-12+MgO+minors, as well as a granular 0-12-12+Calcium (lime silicate) (not slow release), to be used for fall+spring, according to the company (September-April) or a slow release 10-6-11-(2) for Mg+minors, from Bayer, but that one uses aquaperls, which I have no experience with, and is pricey - others, as well... The slow release cannot be sprinkled, since they come in cubes to be placed midway between the stem and the container walls. I have used them in the bigger containers: I had no or really very little leafburn (on some variegates), but this could be on account of the temperatures, and some wind. I could use the 0-12-12 on the young plants, no nitrogen, or find another fertlizer for an additional once a season application - the 9 month release at a reduced rate and, since these are cubes, take them out end of September (May/September or October)- if the mix that contains sulfur (SO3) is more interesting, or use the 6 month - any suggestions would be of immense help, of course. I hope this isn't too long. Thanks again for the info.
I would not use cubes for potted plants. Instead I would crush them up and sprinkle the powdered leftovers around the outside of the can and water the remnants in well. When we talk about timed release fertilizers we are generally referring to the gelatin coated capsules or granules. The cubes are much like our tree stake fertilizers in that we place them in the ground in a triangular pattern, sometimes a rectangular pattern, water the plants well and hope that the stakes will dissolve over time and the nutrients reduced to be able to be utilized by the roots. For Japanese Maples this is not what I would recommend. I'd rather use a granulated fertilizer instead. The main issue is how much nitrogen to apply and for Maples less than 5 years old I let my potting soil mix be my nitrogen source. I use 0-10-10 in the Spring with 6-10% calcium with about 4% sulfur and 2% iron along with some trace elements of manganese and zinc. I use about one ounce per 2 gallon plant, 2 ounces per five gallon plant and apply the fertilizer either right before the Maple leafs out or as the Maple is leafing out. Since I have a much longer growing season than you I can come back in with another application in 4-6 weeks and then I leave the plant alone until the Fall. What is most important to me but certainly not to everyone is that I want a root system to develop more than I want top growth. In the nursery we did not give the Maples any fertilizer at all until they were roughly 4-6 years old and were in five gallon containers. Once we have a well developed root system we will get adequate to good top growth later but with a solid root system I can place these plants in the ground sooner than most people can and expect them to grow on well and live a good Maple's life whereas others will get lush and nice top growth on these plants when they are young but as soon as these nice looking plants are placed in the ground they will have a tendency to stagnate and when a Maple stagnates either in a container or in the ground we can expect something bad that will happen such as abnormal dieback due to Verticillium in the plant or Tight Bark to show itself. Look at Michael's photos in the Bark thread (refer to the link below) and wonder when we see those symptoms. We do not see that kind of stuff on vigorous growing plants too often, we see it on plants that have started to stagnate or are in the process of stagnating. When we see these lesions on the twigs and branches we should take a look at the root system and here is where we see why root system development is more important than top growth. If we had a solid root system the plant can overcome much of the symptoms the twigs and branches are showing as with those symptoms we are guaranteed of having some major dieback and we are looking at the precursor of the eventual demise of the tree if the plant does not produce roots right now and the plant will not produce roots if there was not enough root system to withstand the attack. Without a good root system the trees will perish. So it is up to the plant to generate a root system before the onset of a weakening due to Verticillium, Pseudonomas and blast forms of Erwinia-like Phytophthora otherwise the tree cannot ward of the diseases. Nitrogen can mask the effects of dieback diseases only for so long for us, then when the tree starts to falter in the ground the pathogens will hit with a vengeance. I've seen it all too often. When we look at the older and established trees at Esveld and see photos of Maples at Kew Gardens, Hillier’s, Westonbirt and elsewhere in Europe, keep in mind one thing that those trees are still around because they were not fertilized much in their lifetimes with nitrogen. Yes, it helps that most of those trees are relatively clean but they were not forced to produce top growth when they were young but instead were allowed to produce root system. Some of those trees may have had symptoms of Tight Bark and have Verticillium in their systems as most all Japanese Maples do but because they had a good root system and they were planted in the ground the trees were able to overcome the effects of the Tight Bark. We can live with Tight Bark as long as we have a root system to fall back on. We can see for ourselves with those great plants which is more important for long term stability, top growth when young or root system development. Those plants have lasted the test of time but many of ours here in the US and in recent Japan also will not get to be half the ages, in some Maples not even a quarter of the ages of those plants. It depends on what we want. I'd choose to see my Maples get up to 30 years old and beyond when so many Maples we have today will not get up to 20 years old and much of that will be due to us and our fertilizing regimens when the plants were young, 10-12 years old and less. Japanese Maple Bark Related Issues Jim
Thanks, mr shep - this is sensible advice. I'll stay away from nitrogen until these smaller plants are older - meaning that they have a well developed rootsystem, good for a 5 gallon container, and might try - very conservatively - the 0-12-12 I found. Then find a micronutrient package: in any case your post teaches me not to be in a rush as regards fertilizers in the first place. And use sparing applications in the spring and the fall only. As regards the older plants: the cubes are made of smaller gelatin coated capsules, and I wonder - if I broke them up to sprinkle them along the container - whether I wouldn't destroy the mechanism, and they'd release the whole load at once? (Alternatively, I could try to find a slow release product that comes in the form of small capsules that can be sprinkled.) But you are anyway advocating a granular fertilizer used once (or twice if the weather permits a longer growing season) and not a slow release one, if I understand correctly. In any case I will use any fertilzer very sparingly on the new 5-7 year old maples until I am more confident about them, and have observed the development of their rootsystem. I had already looked at the bark issue thread before, and now again with Michael's photos. What you write about the maples stagnating once placed in the ground, or as they get older, is disconcerting since at least some of us want our maples to outlive us - and to have at least a couple of maples that become like those in Westonbirt that I saw. You relate these bark problems to the rootsystem, and the presence of pathogens that take over the plant when other conditions - an inadequate rootsystem, other cultural conditions - does not allow the maple to fight the disease. I planted a number of maples in the ground - also sugar and red maples - and each time wondered whether the roots were sufficently developed for the size of the plant. In any case, thanks for the advice: it is nearly impossible to get adequate information by just reading a couple of books, or taking word of mouth, if one does not also get the opportunity to hear first hand knowledge that comes from experience. Schusch
What I wrote does not affect me too much but it will some of you out there in cyberland. People assume that we can grow some of the specialty plants like we would grow agronomic crops. This is a huge mistake for certain horticultural plants. We cannot always relate how we can grow a Scarlet Maple or a Sugar Maple with how we have to learn to grow Japanese Maples. We can get by giving some other Maples nitrogen when they are young and we still can with Japanese Maples but most people over do their nitrogen applications and when we do this the plants will pay for it in some way. Even today some nurseries are using enhanced rootstocks, juiced as I call them but all I envision are these microbial aided rootstocks as being a vector for problems later as the tree develops. There is no substitute for vigor in our seedling rootstock for grafting. I am curious to see how well these trees develop over time for their patrons in comparison to the older and established trees in the hosts gardens but again it is a huge mistake to want a lush looking tree when young as there comes a time when the aided trees will slow down in its growth and when the tree slows down too much someone is in for some trouble. It is a rather common event when we see several nice Maples sold in retail nurseries and ten years later wonder why we do not see those plants allover in our local landscapes. Knowing 100-200 nice five to fifteen gallon sized plants were sold just from a couple of local nurseries and being able to pick out and see three or four of those plants still around ten years later makes one wonder what happened to the others. Well, I know what happened to the others. It is never a pleasant feeling to know this part of the Japanese Maple equation. I'd still crush the cubes as even some of the pelleted fertilizers can have the gelatin coats on them. I would not apply all of the residue cube all at once, I'd break my applications down in half or make three or four small periodic applications rather than one large one. Jim
Schusch, Fertilizing maples has been treated in several threads. In this one http://www.botanicalgarden.ubc.ca/forums/showthread.php?t=8446 I informed of my, negative, experience using timed release fertilizer with potted maples. It tends to confirm the statements given by other forum members. Although it may be argued that the results are climate dependent and cannot be extrapolated to other very different situations. Regards, Gomero
Schusch, I cannot adequately express my frustration surrounding the two topics at hand--fertilizers and maple diseases. I can tell you that what you are reading now is something that came to my attention a while back and it is something that I am reminded of every time I walk among my plants. Until I have a bit more time to write, I want to say that what Jim has said is true. While you will not find widespread solidarity about the issue, or many people that will want to talk honestly about it, there is widespread disease in our maples today and it is masked by the way the maples are grown before they get to us. In some cases, we all buy plants too young today to even be able to see what is in them. But after we have had them for a few years, we will begin to see signs. Jim told all of us a long while back in the forms not to buy the names of plants and not to buy them young. He echos that again when he says that they will not live to 20 years old. I have bought a number of 5-7 year plants in the past few years that look very nice at the nursery, but when I get them home and into our hot growing conditions they start to show signs of stagnation and tight bark within a season or two. I beleive this to be the shock of the cultural transition and the fact that I will not treat them with the Nitrogen that they are used to seeing in the nursery setting. I do not blame the people growing the maples as it is their job to maintain a beautiful lush plant to sell. It is just the fact of the matter. If I knew someone who sold clean maples that I could depend on--I would be a dedicated patron. But when we go insearch of the new and the rare, we buy from where ever we can find the plant. This causes us to end up in the forum asking how to fertilize because the plants are not preforming for us like we thought they would. I have surmized that the performance issues with these plants are not fertilizer related. They are quality related. We can push and push all we want, but the risks stated above are real and worth taking note of. This is not meant as all doom and gloom because I have many very nice maples. I am in the process of repotting all of them and I am very happy in many cases. But I will say that if I look at the twigs and the bark before I take the plant out of its container, I can make a good guess about what might be below. Or, I can think back to myself about what I have done to the plant the last year or two with regards to fertilizer and suspect what my roots will look like. I have said many times that I will be patient with my plants, but the reality of how slowly the really grow always comes back to haunt me. Some of the very ornamental and fussy varieties of maples grow VERY slowly. We have to be patient and to try and push these varieties to grow faster is the worst decision we can make. Like Gomero said, we have all tried to fertilize our plants and we all have faltered in some way or another. I have faltered with granulars and and extended release as well as liquids. What our plants need are good roots and unfortunately nitrogen fertilizers don't play a big role there. Stick with you 0-12-12 and some micronutrients and you will have greater success. Another key to the puzzle that doesn't belong here is soil mix for potted plants, but my quick two thougths are that we need to get air to the roots and it needs to drain. If we combine nitrogen with a poorly draining soil we are doomed. Here in Oregon, many of us are finding that we have to go to very light mixes with fir bark and pumice only for our very young plants. Even adding a little loam on a young maple to retain water can bog down the soil enough that the roots will not grow. If we add peat and the soil begins to compact the maples will not grow. It seems absurd, but many of the rootstocks on are plants are not strong enough to grow in heavier containerized soils when the plant is very young. If we start fertilizing these underdeveloped stressed root systems we invite water molds and bacteria to come in and destroy our plants. I will tell you that tried that scenario this past summer and it was quick and painful death to some of my young plants.
Gomero - thanks for the reference to the other thread. The climate should be a factor if the fertilizers get reliably released with higher temperatures and more moisture - you could then have more problems with them than me, who lives higher up in Europe. May be. However, Esveld, located in the Netherlands, thus closer to where I live, do not seem to use any chemicals on their new maples anymore for environmental reasons, but also for the same reasons Mr Shep and MJH are talking about. On their website - I included the link above - they refer to various problems that originate in the use of these chemicals - this would be doubly true for their excessive use. They seem to try to address these issues in their new growing method - here is a description of their results: "the development of the plant and leaves is less vigorous and more compact. Also the leaf colouring becomes much more intensive and the root system is a lot better. In short, a much healthier plant but also a smaller plant is produced. Our plants are not as vigorously grown as they used to be, but will be able to withstand much better any attack by funghi and other diseases" MJH - I'll definitely try the 0-12-12 + micronutrients. (The one thing I am trying to figure out is the use of calcium - the product description calls it 'lime silicate' (in French) and advocates its use to work against the acidity of the soil. I know calcium raises the PH of the soil - and maples do not need a higher ph - but also that calcium is a crucial element in any good nutrional regime. How do those work together?) A good soil that provides sufficient air and drainage could also improve and neutralize the dangers that come with the fertilizer. As regards the slow growth - I can see how this is a problem for a commercial grower who has to contend with the clients' expectations, and may be misconceptions: otherwise Esveld wouldn't have to explain that slower growth can equal a healthier, better plant. For the private owner slow growth on maples doesn't necessarily have to be frustrating since maples have a subtle beauty anyway. Plus one can always buy two, rather than one... Ideally one could do what they do in Westonbirt, where I saw that they are growing a whole number of new japanese maples in a wooden setting, with conifers around that will naturally help those maples along. They indicate that the decisions made by the first owner in the mid 19th century (!) make for the maples, and other plants we can see today. So, slow growth ...
"Our plants are not as vigorously grown as they used to be, but will be able to withstand much better any attack by funghi and other diseases". We cannot equate slow growth and even growth as being the same. The nurseries that have spent some time seeing how their plants do elsewhere are the ones that will realize just how important even growth is. Even while the plants are putting on roots, the top growth is not stymied but is actually more consistent. With the top growth process we get stem elongation in which with overly vigorous growth we get stem laterals much too long with much less leaf volume as a result of less leaf nodes than we will get from even growth. The nice thing about not having super lush or enhanced vigorous growth is that once we place these plants in the ground the roots will try to grow first and establish themselves rather than us see a whole bunch of new top growth. In a year or two we will see moderate top growth so in effect we never do see slow top growth when a plant is producing root system. We usually see an even, sustained growth instead. When we see an overly vigorous or pushed plant stop its growth and stagnate is when it will falter. We will see more leaf scorch then, more dieback, less new growth replacement and we may even lose the tree if it does not snap out of it but once an enhanced tree starts to become susceptible to perpetual leaf burn and twig dieback it really never does recover unless we catch it in its early stages and whack the plant back hard and force it to put on root growth. People new to the business or relatively new to Maples just do not understand this stuff. Yes, nice looking plants move out the door fast but it is our responsibility to know how these plants behave once they are in the ground for several years. Some Maple cultivars are not made to last any real length of time and we tell people of this fact as some Maples life expectancies are not very long compared to others. This is no real fault of anyone's but when we are dealing with standard plant material it will and does matter how long these plants live for people away from the nursery. Jim
This is what is critical and it has taken me 3 or 4 years to finally realize what it happening. It is this process that tricks the unknowing grower into wanting to fertilize. We get a beautiful plant with nice lush growth and bring it home and pot it up. Then we watch the new growth slow and the leaf scorch set in. This is particularly easy to have happen here in the hot valley. We then get a new set of leaves, many of which will be lost. If we allow this to perpetuate itself over a couple of growing seasons, the plant is now in a very bad situation. It was last year, that in discussion with another grower, we came to the conclusion that cutting back our stagnate mapels might be just what they needed. It is no big deal as they are quite young. I am currently repotting everything to take care of root issues and the pruning will come soon or this summer. By pruning in the summer we can see some redirected growth in our long season. This plan combined with the non-nitrogen fertilizer program will hopefully get those troublesome plants back on the right track. As for the way Esveld and some others are growing their maples in a more "environmentally" friendly manner, I have some concerns for myself. If growers in cooler climates use mycorrhizal fungi additives to assist in plant developement it could mean trouble for container growers in warmer climates as well as people planting these maples in the ground soon after they get the plant in soils that are not suitable to fungal colonization. If a grower in the northern part of Oregon, where it is cooler and wetter, uses fungi to enhance a plants growth, what happens when I bring it down here and put it in either a pot or our heavy clay soils? When it is over 100 degrees for a few weeks in the summer the fungi will be wiped out for the containerized plant and they will not survie most of our planting conditions for any length of time if we use native soil. Without the assistance of the fungi, the plant will become stressed, stagnate, and suffer die back and leaf burn. It would be like instantly reducing the root system when we lost the fungi. I could be wrong here.......but this process of adding mycorrhizal fungi is not much different that using nitrogen to grow bigger plants. The resulting problems are the same for the end-grower of the plant.
