This little seedling came from my neighbors' beautiful Japanese maple. I would like to try to keep it. It splits into two branches about 10 cm above ground. My question is whether I should keep it with two branches or whether I should chop off one of them (and perhaps wire the seedling straight). Any suggestions?
I like the look of Japanese maples with two trunks, but there are others who do not; the aesthetics are down to your personal choice.
Practical considerations are mainly to do with the what the winter weather in your region is like and the potential for possible damage from snow load. Many people in areas subject to very heavy snow falls will avoid V shaped trees at all costs.
If you decide to remove one branch I would not do it yet. Instead, stake the new leader upright and just pinch the growing tip out of the other branch to inhibit it from growing longer. Then either prune off the unwanted branch in the fall, or let it remain for a year or two longer and then remove it.
It really helps me to look at other trees in similar locations to where my planting will be and see how they are pruned.
Lowe's of all places has a number of some non-japanese maples growing in their parking lot islands. They had left them with many trunks and it generally works. I decided to split the difference on my generic acer palmatum and go with three trunks.
I have one large two trunk shaggy triflorum and love it, not sure how else to describe it. I also have a two trunk griseum, but it is far behind in size, not so much age. Most of the Japanese maples are single trunked higher or more generally branching from two to many more, which is their nature. I have seen that they will find their way. In fact most of my trees were planted at 5 years or just a little younger, and they found their structure. I let them and pruned to assist only. I'd let any really young maple stay in a pot for a few years before planting in the landscape, and this looks pretty young.
Hm. This one just sprouted by itself in the front yard; I didn't plant it. I don't even know which year it's from. I previously tried growing J. m. seedlings in pots, and they all died. This one may be safer untouched by me altogether :)