PlantFiles: Red Maple, Scarlet Maple
Acer rubrum 'Red Sunset'

So we purchased this maple as a 15-gal tree 10 years ago. We live in No California (San Jose) and it is hot in the summers and not very rainy so it is on a drip system for watering. It maybe is 12 feet tall and I am wondering if it is growing very slow. It drops beautifully in the Fall. Also how do I prune it -- we never have. The leaves are full on each limb but some limbs are too low on the truck and not filling it the tree as a whole. Thanks for any help provided.

We've been at this house for a little over 10 years and my neighbor has 3 'Red Sunset' Maples in her yard. They were already planted before we built our house and the trees have gotten more beautiful over the years! I really like the fact that the one closest to us makes a great shade tree in the Summer! She and her DH live behind/next to us and she's a good neighbor and says that it's ok to take photos of her trees. 'Red Sunset' is gorgeous in the Fall with its beautiful colors!

Fall of 07, the colors started to turn early, then went all green (the colored leaves had already dropped). We've had an unusually long, very dry and very hot Summer that included parts of Spring and Fall.

Acer rubrum 'Red Sunset' (R) RED SUNSET RED MAPLE Dec (z4) (Cut)
A highly-rated and reliable red maple, this vigorous tree to 45'has a strong branching pattern & foliage which is lustrous green in summer & brilliant shades of red in fall. Sun/Med-damp

This is a lovely tree. We lined our driveway with them when we built our house 10 years ago. We bought very large trees, with trunks of about 3 inch diameter. When you plant trees that large, they start off slower in growth. Now, after 10 years, these are quite large trees and really lovely. The Red Sunset Maple has much smaller leaves than sugar maples or some other kinds. They are a rich green in summer and very dense, giving dense shade. They tend to start out looking awkward as youngsters, and then obtain a very round shape with maturity. Be patient with regard to the shape. They have a lovely rather smooth silvery bark. In fall they are a gorgeous true scarlet red; however we find that the leaves don't stay on the trees all that long as compared to sugar maples. The first strong wind or rain brings them down quickly -- and they are among the first to color. We have also been told that they are not the longest lived of maples. We, in fact, lost two of them after 8 years due to a double whammy of fireblight (unusual in maples, but happened that year) and then a massive caterpillar attack. Knowing what we know now, we would not line the driveway with them if we could do it over. We would probably use sweetgums instead. However, I do still recommend the tree as a lovely landscape addition. Just be sure to water them regularly in their first few years -- if you don't get an inch of rain for over a week, water them deeply with some type of slow-trickle method. We use spackle buckets with a small hole punched in the bottom. They stress from lack of water and will get a wilted look. A beautiful tree with the best red color, but perhaps not as hardy as some other cultivars.
ADDENDUM 2011: These trees apparently do not hold up well to heavy ice. We had a devastating ice storm here two years ago that did heavy damage to all our "Red Sunset" Maples. Some split completely down the entire tree into the trunk and were a total loss. Many had the tops broken out, large branches snapped off or badly bent. They were basically all ruined after 15 years of taking special care of them -- we are heartbroken!