Our Native and Non-Native MAPLES

Japanese Maple - various fall colors

The Red Maple (Acer rubrum) is one of the most easily recognized trees on the Nature Preserve with its broad, deciduous, palmately veined leaves. The veins of the leaves spread out from the base like fingers. This is more easily seen in the non-native Japanese Maple (Acer palmatum) that is widely planted as an ornamental. Worldwide there are nearly 150 species of maple in the Northern Hemisphere. The United States has about a dozen species and Delaware has three native maples. The winded maple seeds are called samaras. As kids we called them helicopters. The Sugar Maple (Acer saccharum) which is commonplace in Pennsylvania northward throughout New England and Canada is only found naturally occurring in New Castle County. A much beloved tree and the symbol of Canada, it has been widely planted throughout Delaware.

We have two native maple species growing on our lands. Red Maple, or Swamp Maple, is by far the most commonplace and can be seen on every tract.

Red Maple - newly emerged leaves
Red Maple - branching pattern
Red Maple - red leaf petioles (stems)
Red Maple - red samaras
Red Maple - bountiful samaras
Red Maple - eyespot gall-insect damage

To my knowledge the more unusual Box Elder (Acer negundo), or Ash-leaved Maple, only grows as a few individual trees on the Isaacs-Greene Tract. It is my belief that these trees are escaped seedlings from some long-disappeared farmyard. The Box Elder has long been planted as an ornamental tree although, to me, it has its setbacks. The trees are host to the reddish box elder bug which over winters under shingles, behind shutters, finding every crack, crevice, or open window of your home. There were two box elders beside the back door of my aunt’s home in Millsboro and she learned to dislike them a lot because of those bugs.

Box Elder - Isaacs-Greene tract
(M-11) Box Elder - aka Ash-leaved Maple - Isaacs-Greene tract

Maples are frequently planted as ornamental and shade trees. Their broad leaves make ideal shade and most of them turn beautiful colors in autumn. Some varieties have specifically been selected for their leaf color. “October Glory” is favored as a street tree for the red autumn foliage. Others like the introduced Norway Maple (Acer platanoides) were selected for summer leaf color such as “Schwedler”, purplish-green, and more recently “Crimson King”, for its deep burgundy leaves.

Crimson King - Norway Maple - varietal selection

Crimson King - Norway Maple leaf detail

Sugar Maple - branch structure
Sugar Maple growth pattern

The Norway Maple is not planted as a streetside tree because of its low crown height but finds favor as a specimen tree in parks and yards. Experts discourage the planting of exotic species. I will add one note here: when I lived in Europe, there was a little lane which ran parallel to Lake Wannsee, in Germany, that was planted on both sides with Schwedler maples. It was magical to slowly cycle through that lane as the sun filtered down through those trees.

Norway Maple - grown in open setting
Norway Maple - leaf and samara detail

The Norway Maple is native to Germany, as well. It can be challenging to tell the alien Norway Maple from the native Sugar Maple. So here are a couple of tips. If the samaras are present notice the distinct difference between the two. If no samaras are found, pick an actively growing green leaf and break the petiole. The Norway Maple exudes a little milky sap. (see photo)

Norway Maple - milky sap in leaf stems

Three of the maple species I’ve mentioned can be used to make maple syrup. This is accomplished by gathering the sap in late winter then evaporating the water off, usually by boiling, and concentrating the sugars to make the syrup. The biggest difference is that the Sugar Maple has the higher sugar content in the raw sap when compared to Red Maple and Box Elder. Author Euell Gibbons (Stalking the Wild Asparagus) claimed to prefer the taste of Box Elder syrup, which I would like to try. Several neighbors of Mr. Abbott used to collect sap, both from introduced Sugar Maples and Red Maple, to make syrup. When purchasing expensive real maple syrup, keep in mind it takes about...

30 gallons of sap to make one gallon of syrup.

Maple sugaring bucket and spiles

While maples have a lot of advantages as yard trees, they do have some negatives, as well. The roots grow close to the surface forming a dense mat that is difficult to grow anything else. Only a few ground covers or tough shrubs survive.

Since they are swamp trees, the roots seek out the minutest seepage of water and quickly completely pack the drainpipe. The damage costs homeowners and cities millions of dollars a year.

Annoying Maple's surface roots

The Silver Maple (Acer saccharinum), that is native to the mid-section of the United States, was widely planted in the last century. The leaves are deeply incised, and the samaras are large and flat. It grows even more swiftly than the red maple, but the limbs are easily broken in a storm. In addition to their surface roots, silver maples have a tendency to grow a large bole of exposed roots around the trunk making mowing very difficult.

Silver Maple - large samaras

Hundreds of varieties of Japanese Maple are offered by nurserymen. Some are dwarf with finely dissected leaves, others have unique leaf shapes or coloring. Even seedlings from the same tree can grow with many colors of leaves and forms. They are favored as specimen trees in lawns and gardens. It is hard to imagine a Japanese garden and Koi Pond without the presence of them.

Japanese Maple - filtered light

Japanese Maple - Fall color variation

Many of our grandparent’s generation, including my father, referred to a completely unrelated tree as “Silver Maple”. This a type of poplar from Eurasia, the White Poplar (Populus alba). These trees were introduced into the United States as ornamentals and now are widespread around the country. They can grow to be quite large but are usually seen as groves, since they have the annoying habit of sending up suckers everywhere.

White or Silver Poplar - NOT a maple

Our family used our two trees as weather forecasters by watching to see if the leaves showed their snow-white underside as the windspeed increased. When the leaves turned over, get prepared, the storm was going to be violent. The white poplar is tolerant of salt air and can be seen growing along our coastline. If you’d like to see one, there is one growing in the private yard at the intersection of Lindale Road and Abbott’s Pond Road.

Some other terms heard in reference to maples are curly, fiddleback, burl, quilted, and bird’s-eye maple. These refer to the grain pattern of the finished wood and not necessarily any specific species. For example, fiddleback maple, as seen on the backs of fine guitars, violins, etc., occurs in Sugar Maple as well as Red Maple, and probably many others. My father-in-law taught me that bird’s-eye maple was the result of a tree developing “sap knots” (his term). This condition can be seen before the tree is harvested.

Red Maple-growth condition indicating Bird's-eye lumber
Sugar Maple - Sapsuckle Woodpecker damage

I hope you can get outside and search for all these wonderful types of maple.

Happy Hiking!

Photos by the author.

The editors encourage you to only plant native species whenever possible.

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