Now that autumn has blessed us with its presence, the vibrant colors of fall will be commencing all over our region soon. Mother Nature will whip out her brush and paint breathtaking swathes of gold, orange and red in both our landscapes and our native habitats, signaling the approach of the dormant season. The vast array of exquisite deciduous plants we utilize here in our local gardens exemplify the ultimate fall colors, some of which I have mentioned before and others I will surely pontificate on in the future. But for this week, I am going big and exploring a couple of wonderfully useful shade tree species for our climate – Acer rubrum (or what we refer to as Red Maple) and Acer platanoides x truncatum (a hybrid Norwegian/Shantung Maple). The cultivars in both of these species are perfectly suited for the PNW as they do not mind our wet seasons, offering gardeners some useful options for a shade tree.
Now first and foremost, when I say shade tree I mean a tree that casts shade, not one to be grown in shade. The trees in our discussion today mature into stately yard specimens, providing summer shade and shelter for wildlife while also adding height and structure to any landscape. They are suitable to use in any garden that has a sunny exposure (not necessarily all day), keeping in mind that nice and even sunshine in an open location will always result in a healthy, well-balanced tree specimen with minimal issues.
When planting them, applying a simple organic transplant food like Sure Start from E.B. Stone Organics is perfect, and mixing in compost with your native soil is even better. Try to dig your hole twice as wide and deep as the pot your tree came in, ensuring your freshly found botanical treasure has an adequate space in its new home. Mulch after it has been planted with more compost goodness or some bark, but be careful not to pile it up onto the trunk. The soil level should ALWAYS stay the same as it was in the pot! Once settled in, an additional dose of an organic tree/shrub type fertilizer each March will help as well; but in all honesty, if your specimen is thriving nicely you may not need to apply an annual dose, unless perhaps you would like it grow a little quicker. Slow and steady is the way of the tree and if you ask me, you should just let it be.
Pruning should be done later in winter in order to address structure issues, or even to thin out interior branching if you desire a more open canopy. And please choose the right variety for your spot in order to let it mature properly in your garden, it pains me to see trees like this butchered into little round balls. Also, topping your trees will only create an eye sore, in my humble opinion. One can always consult with a certified arborist when tackling pruning, particularly with older specimens or anything potentially hazardous.
Here are a few of my favorite Red Maples, all cultivars of Acer rubrum…
‘Red Sunset’: One of the finest flavors ever hybridized and possibly the most widely planted tree across North America. It reaches roughly 45-feet tall by 35-feet wide, has an oval shape and glowing red to orange fall color.
‘October Glory’: A spectacular variety that turns color a bit later than others. It reaches roughly 40-feet tall by 35-feet wide with a large rounded crown and stunning reddish-orange fall color.
‘Redpointe’: One of the newer and more useful modern varieties with a refined silhouette. It reaches roughly 45-feet tall by 35-feet wide, has a tidy broad pyramidal shape and fiery red fall color.
‘Armstrong Gold’: An extremely useful type with a tidier narrow form for a smaller garden footprint or for even a street style location. It reaches roughly 40-feet tall by 12-feet wide with a columnar habit and golden-orange fall color.
‘Red Sentinel’: A newer introduction, the perfect marriage of vibrant foliage and a tidy columnar habit. A great choice for streets, parks, and tighter urban landscape spaces, it reaches roughly 40-feet tall by 18-feet wide, is anthracnose resistant and has a bright red fall color.
Another group of maples must be mentioned here as well… Norwegian Maple (Acer platanoides). It has large foliage and is extremely cold hardy, but typically does not change color much in the fall except to a browny yellow. Acer truncatum, or what is called Shantung Maple from China, is known for its glossy green summer foliage, excellent fall color, heat tolerance and adaptability in various soils. These are also very insect resistant, including to a pest that is moving into our climate called the Japanese Beetle. These two species have been hybridized into a number of worthy landscape trees that boast excellent foliage, durability and bright fall foliage.
‘Urban Sunset’: A lovely specimen that produces a tidy crown and is nearly seedless, perfect for small yards or as a street tree. It reaches roughly 30-feet tall by 25-feet wide with a narrow pyramidal to oval shape and deep red fall color.
‘Pacific Sunset’: One of the first hybrids and still one of the best, this variety colors up a bit sooner than others. It reaches roughly 30-feet tall by 25-feet wide, has a spreading rounded crown and orangey-yellow to red coloring in the fall.
‘Norwegian Sunset’: Another useful “oldie but goodie”, these mature into wonderful landscape trees with excellent branching and a balanced, uniform canopy. It reaches roughly 35-feet tall by 25-feet wide with an upright oval shape and orangey-yellow to red colors in the fall.
‘Crimson Sunset’: This variety provides interest spring through fall with purplish leaves during the growing season versus the typical green. They are super heat tolerant and more compact than older cultivars like ‘Crimson King’ or ‘Crimson Sentry’. Tree reaches roughly 35-feet tall by 25-feet wide, has an upright oval form and it turns maroon to bronzy-purple in fall.
‘Ruby Sunset’: This variety is certainly one of the smallest “shade” trees around but its dense and compact shape makes it perfect for some summer shade. It reaches roughly 25-feet tall by 20-feet wide, has glossy green foliage throughout the season, a broadly rounded canopy and fiery-red foliage in fall.
Quite a few of both of these maple groups have been hybridized by PNW breeders, mostly by one of my favorite wholesale tree nurseries called J. Frank Schmidt and Son. Their website is fabulous if you want to explore both pictures and descriptions of all kinds of fun arboreal options.
I truly hope that we can all agree on this simple statement; one thing our planet will always need is more trees. From helping to clean our air and producing oxygen to cooling our homes, the jobs trees do for our environment is both necessary and miraculous at the same time. Take a peek around your landscape to see if any of these trees may help you and then stop into your local garden center to experience their brilliant changing colors in person. Always remember that fall has been, and always will be, an ideal time to plant just about anything. Speak with a Certified Professional Horticulturist about your needs and allow them to help you pick the perfect specimen(s) for your garden. I will continue to say this when it comes to trees, the best time to plant one was twenty years ago, the next best time is today!
Remember, leaves up and roots down…
Trevor Cameron is a Certified Professional Horticulturist (CPH) and serves as General Manager for Sunnyside Nursery in Marysville, WA. He can be reached at sunnysidenursery@msn.com.
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