ACER GRISEUM PAPERBARK MAPLE

This month’s woody plant is a favorite for many gardeners for a myriad of reasons. Acer griseum, also known as the Paperbark Maple, is a small ornamental tree that should be added to more gardens across your client base.

Paperbark Maple is a smaller maple – in the 20-to-30-foot range – with a width slightly less than its height, creating an oval-shaped crown with upright branching. As the common name suggests, the bark is one of the ornamental features worth noting as it peels in thin, paper-like sheets each fall. The bark has a beautiful cinnamon red/brown color and brings incredible winter beauty to the landscape. This is a tree that demands an up light washing the crown to get the bark peels to really show off their beauty through the entire year.

People often don’t recognize this as a Maple at first because they are used to leaves like Sugar (Acer saccharinum) or Red (Acer rubrum). Paperbark Maple is one of the tri-foliate maples, meaning the leaves are compound (split) into three parts. Around 3 to 5 inches long, the leaflets are coarsely toothed with the middle leaflet being held on a short petiole. Bright green above with some hairs, flip the leaf over and you’ll see many tiny hairs giving a blue-green hue to the leaf. In fact, the specific epithet “griseum” comes from the Latin word griseus, which means gray. This is in reference to the blue/green/gray color of the underside of the leaves.

Most authorities often state flowers of Maples as being insignificant as a reference to their ornamental quality. While the flowers aren’t going to stop the show like a magnolia, we’d argue that maples have beautiful flowers. They aren’t going to be a selling point with your clients, but for the plant nerds in the group, Maple flowers are well worth noting. On Paperbark, the flowers are a soft yellow, pendulous cluster, like a group of tiny, yellow bells. They emerge as the leaves are continued on page 26

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continued from page 24 unfurling, usually in mid-May. Maples are also often described as being wind pollinated. While that may be true, they are also insect pollinated and provide a key source for pollinators. Don’t trust people who say this doesn’t support our pollinators because it isn’t a native tree – just go outside and look at the tree in bloom and you’ll have all the evidence you need that our pollinators are happy to visit.

Seeds are quite noticeable on some specimens of Paperbark Maple. Just like all Maples, the fruit is a samara (seed with wing) that we often call helicopters. The seed part of the helicopter is swollen, and the wing is long with the two being held between 90 and 60 degrees apart. They turn a nice deep brown and are often held well into the winter. You won’t have a mess of maples like our native reds and silvers, as most of the seeds on paperbark are void.

There are plenty of options to consider when deciding where to plant a Paperbark Maple. Typical clay soils are OK for this tree, so long as it isn’t too wet for too long. It will also be at home in loams and sandier soils. Soil pH won’t have a big impact on their success, so long as you don’t stray too far from neutral to slight acid. Ideal exposure is full-sun to part-shade, benefiting from a little reprieve from hot afternoon sun in the middle of summer. While we typically consider this as a specimen tree, perhaps a grouping of three or five would really up the impact of the bark features and fall color. Another great location for the tree is in the tree lawn and under powerlines. It should stay short enough to escape the dreaded utility hacking.

Acer griseum was discovered (to the western world) by famous plant explorer E.H. Wilson who brought trees back from China to England in 1899. Shortly after the introduction to the Royal Horticultural Society, the plant was shared with Arnold Arboretum and introduced into the United States.

While it is unlikely to find any cultivars on the market, there are some impressive hybrids. What is the difference, you ask? A cultivar is still the straight species with a unique feature (usually flower color, or size, or something observable). A hybrid is the result of two different species of plants cross breeding with their offspring being the hybrid. Many nurseries across the plant world have toyed with hybridizing Acer griseum with the best results coming from crosses with Sugar Maple and other, more commonly available, Acer maximowiczianum (Nikko Maple).

We often like hybrids due to a phenomenon known as “hybrid vigor,” referring to the often-improved growth of hybrids in

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ADDRESS: 9718 AVON LAKE RD, LODI, OH 44254 the plant world. The reason for this improved growth would be an entire lesson in genetics, so for now, let’s just go with the hybrid vigor phrase.

Girard’s nursery in Geneva (now closed) was a source of some of the first hybrids and is often honored by the name “Girard’s Hybrid Paperbark Maple.” This hybrid loses some of the papery flaking of the bark, being more of a tight curl held close to the stem, but still holds the beautiful cinnamon colors. It will grow faster than either of the parents even more brilliant fall color.

You may come across other cultivars of the same hybrid, but they will perform the exact same as the Girard forms and don’t need a unique name other than Girard. The only unique cultivar we have come across in our plant hunting is ‘Cinnamon Flake’ that has such tight curls in the bark that the ornamental appeal drops off.

Jim Funai, PhD, is full-time faculty at Cuyahoga Community College, a NALP accredited associate of applied science in hoticulture degree program. He has a PhD in Landscape Engineering and Forestry and is a Licensed Arborist. Shelley Funai is Grounds Manager at Stan Hywett Hall and Gardens in Akron, Ohio, which offers a historic estate designed by Warren H. Manning and a beautiful manor house museum. She is Landscape Industry Certified in Ornamental Plant Care.