Acer saccharinum Seeds | Silver Maple
LATIN NAME: Acer saccharinum
COMMON NAME: Silver Maple
Plant Profile
A silver maple shows you the wind. Every leaf is pale, almost white beneath and glossy green above, so the crown flickers from green to silver with each gust. The leaves are deeply cut into five narrow lobes with sinuses that nearly reach the midrib, giving them a star-like outline unlike the softer, fuller leaf of most maples, and they hang on long, flexible stalks, which is why the whole canopy shimmers rather than merely rustling.
Silver maple flowers before it leafs, opening on bare twigs in dense tufts on unusually long stalks. There are no petals; the flowers are greenish-red and carry either stamens or a two-lobed pistil, and although both kinds usually occur on the same tree they sit in separate clusters. Wind carries the pollen at a moment when almost nothing else is flowering, and the nectar feeds the first bees and flies of the year. The long flower stalk is one of the easiest field marks, because the red maple’s flowers sit almost against the twig.
Silver maple can be tapped in the same way as sugar maple, and the plumbing of the tree is the reason the whole maple syrup industry works: sap moves under pressure generated by alternating freezes and thaws, as gas bubbles form in the frozen xylem and then draw sap in from the roots when the wood thaws, and the tapper’s spile collects the surplus. Silver maple’s sap is thinner and less sweet than the sugar maple’s, so it takes more of it to make syrup. As a garden tree it is planted for quick shade and for wet corners, well away from paving and foundations.
Science & Biotechnology
Maple research has moved in three directions that touch this species. Riparian planting programmes use fast-rooting maples, silver maple among them, to hold stream banks and to strip nitrate from shallow groundwater before it reaches the watercourse, and the same tree has been tested in phytoremediation work on road salt and heavy metals. Clonal propagation is done by axillary shoot culture, with nodal explants proliferating on cytokinin and rooting after an auxin dip, and somatic embryogenesis has been achieved in several Acer species. Molecular work on maples has meanwhile concentrated on the sugar maple and red maple genomes.
Uses & Benefits
Speed in a tree is usually paid for somewhere, and silver maple pays in wood quality. Fast growth lays down wide annual rings with a large proportion of thin-walled earlywood vessels and comparatively little of the dense latewood that gives timber its strength, so the limbs are weak relative to their size. Add narrow branch angles and included bark in the crotches, and the result is a tree that sheds branches in ice, wind and wet snow. A wide, shallow root system, meanwhile, spreads far beyond the crown and finds drains and irrigation lines.
The lumber trade sorts American maples into hard and soft, and silver maple goes into the soft pile with red maple and boxelder. Soft maple is markedly lighter and softer than sugar maple, at roughly half the hardness, and it is a diffuse-porous wood with no pronounced figure, so it is not sold for flooring, tool handles or butcher blocks. Instead it goes into furniture frames and internal parts, plywood and veneer cores, pallets, crates, mouldings, turned items and pulp.
Growing from Seed
The leaf characters are the cleanest way to sort a silver maple from the red maple growing beside it in the same wet woods. The red maple leaf has three broad lobes with shallow notches and a red stalk; the silver maple leaf has five narrow lobes cut almost to the centre, a pale frosted underside and a stalk that snaps easily in the hand. Autumn colour is a soft yellow rather than the red of its relative, and the bark on old trees breaks into long shaggy strips.
The seed must be sown green. Collect the samaras as they colour in late spring, before they dry on the tree, and get them into a damp, loam-based mix within a short time, pressing each one in about a centimetre deep and spacing them five centimetres apart. Prick the seedlings out as soon as the first true pair of lobed leaves opens, pot them on individually at the four-leaf stage to stop the long taproot coiling, and grow them on in a sheltered frame. Plant out at around a metre of height, at six to ten metres for a shade tree, and prune for a single central leader so the heavy limbs start high.
Our Take
Plant silver maple where its speed is wanted and its weakness does not matter, then set the slower maples where they can be seen properly. The red maple is the natural comparison in the same wet woods and a much better long-term tree, and Acer rubrum will give you the scarlet autumn the silver maple never quite manages. For real timber and real syrup, plant the sugar maple: Acer saccharum is slower, harder and worth the wait. Boxelder is unstoppable on wet ground, so Acer negundo makes a useful nurse tree on a raw bank.
Related Reading
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