Hi All!, Im new to this forum and would love some help identifying what is wrong with my Autumn Glory Maple (Acer Rubrum). I currently live in warm, sunny Brisbane Australia, and we easing into our fall weather, but it is still around the 70-80s. Unfortunately, for the past 2 months, my leaves have turned brown and discoloured. Its currently in a large pot, located in sun from dawn to about 1pm then gets shade the rest of the day. I am currently watering it every other day (hot weeks everyday). It is still budding and new shoots come up, but then after a week, they tend to turn brown. Can anyone help me identifying the problem? Is it getting too much water? Sun scorched? Or could it be an internal sickness? Thanks for your help!
Welcome to the forum! I suspect that you are watering when the surface of the soil is getting dry. But the bottom of the roots are staying too wet. I would remove the dish at the bottom of the pot and ensure that it is draining properly, then keep it off. The roots need oxygen in order to take up water. If the roots are too wet, it limits the oxygen and the roots can't take up water to keep up with the water loss in the leaves through transpiration. Also, there is nothing a maple hates more than wet feet and removing the dish will allow those feet to breathe. Anyway, that would be my first recommendation before considering something more complex.
Acer rubrum is also known as "Swamp Maple" and doesn't mind water like most of the genus. (I've got it growing well in areas that see standing water during winter). That said I agree with JT1 that you should remove the dish and let the pot drain freely. It may be sitting in a puddle, and while that might work in the landscape it might be difficult in a pot with a much smaller root mass. Another thing to consider is if somehow the soil has gotten very alkaline, that might cause what you see. Otherwise this should be a very easy maple to grow, and I don't think it will be worse for wear next year. Since it's the end of the growing season, it may look pretty shabby if it's been undergoing stress during the year. -E
Thanks for the information! I'll try it out and remove the dish and let it drain freely. For what its worth, in the bottom of the pot I 've put a layer of larger stones to help with the draining process, but I wonder if it is still to wet for the roots. Also, should it be getting a full day of sun, or is it best to have plenty of shade for the rubrum? Thanks for your help!
