Box Elder
Acer negundo
Family: Aceraceae
What it is like
The boxelder is an undesirable tree for many urban situations and in some cities, planting it may be illegal. The undesirable characteristics are brittle, weak wood, short life, susceptibility to boxelder bug, and trunk decay. But the tree will grow just about anywhere and therefore it may have uses due to its adaptability. The best thing about the tree is that it will grow on adverse sites where more desirable trees may not.
Acer negundo is a deciduous Tree growing to 21 m (69ft) by 8 m (26ft) at a fast rate. See above for USDA hardiness. It is hardy to UK zone 2. It is in flower from April to May, and the seeds ripen from September to October. The species is dioecious (individual flowers are either male or female, but only one sex is to be found on any one plant so both male and female plants must be grown if seed is required). and is pollinated by Bees. The plant is not self-fertile. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils, prefers well-drained soil and can grow in heavy clay soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist soil. The plant can tolerates strong winds but not maritime exposure.
Height (m): 21
Where it is found
Found in a variety of soil types, growing best in lowland sites along rivers, streams, ponds or seasonally flooded flats.
N. America - Nova Scotia to Florida, west to California and Manitoba.
Conservation Status: This taxon has not yet been assessed.
Countries/locations it is found in
How it is used
Food
Rating: 3
The sap contains a reasonable quantity of sugar and can be used as a refreshing drink or be concentrated into a syrup. The syrup is used as a sweetener on many foods. The sugar content is inferior to A. saccharum according to one report whilst another says that it is highly valued as a producer of sweet sap. The sugar from the sap of this tree is said to be whiter than that from other maples. To obtain the sap, bore a hole on the sunny side of the trunk into the sapwood about 1 metre above the ground at anytime from about January 1st until the leaves appear. The flow is best on a warm day after a frost. The best sap production comes from cold-winter areas with continental climates. Inner bark - raw or cooked. It can be dried, ground into a powder and then used as a thickener in soups etc or be added to cereal flours when making bread, cakes etc. The inner bark can also be boiled until the sugar crystallizes out of it. Self-sown seedlings, gathered in early spring, are eaten fresh or dried for later use. Seeds - cooked. The wings are removed and the seeds boiled then eaten hot. The seed is up to 12mm long and is produced in small clusters.
Inner bark: the bark that is found just beneath the tough outer bark of trees and shrubs.
Sap: usually of trees and usually but not always used as a drink.
Seed: includes nuts, cereals, peas and beans.
Sweetener: includes sugar substitutes.
Medicine
Rating: 1
A tea made from the inner bark is used as an emetic.
Emetic: Induces vomiting.
Other
Rating: 3
The leaves are packed around apples, rootcrops etc to help preserve them. A fairly wind-tolerant tree, it can be used in mixed plantings as a part of shelterbelt plantings. Wood - soft, weak, light, close grained. It weighs 27lb per cubic foot. Of little commercial value, it is used for boxes, cheap furniture, pulp, fuel etc. Large trunk burls or knots have been used to make drums.
Musical: Specific mention of plants used as musical instruments. Does not include the various woods that can be used for making musical instruments.
Preservative: For food, or for treating wood, ropes etc.
Shelterbelt: Wind resistant plants than can be grown to provide shelter in the garden etc.
Wood: A list of the trees and shrubs that are noted for having useful wood.
How it is grown
Of easy cultivation, succeeding in most soils but preferring a rich moist well-drained soil and a sunny position. Grows well in heavy clay soils and in sandy soils. Plants often become chlorotic on very alkaline soils. Plants are hardy to about -18°c. A fast growing but short-lived tree in the wild, living for 75 - 100 years. It is fairly wind-tolerant, but the branches have a tendency to break in strong winds. This species is cultivated commercially in Illinois for its sap. Another report says that this is one of the least productive species for sugar. A very ornamental plant, there are several named varieties. This tree is a bad companion plant that is said to inhibit the growth of neighbouring plants. This species is notably resistant to honey fungus. Very tolerant of pruning, it can regenerate from old wood if it is cut back hard. Dioecious. Male and female plants must be grown if seed is required.
Propagating it: Seed - best sown as soon as it is ripe in a cold frame, it usually germinates in the following spring. Pre-soak stored seed for 24 hours and then stratify for 2 - 4 months at 1 - 8°c. It can be slow to germinate. The seed can be harvested 'green' (when it has fully developed but before it has dried and produced any germination inhibitors) and sown immediately. It should germinate in late winter. If the seed is harvested too soon it will produce very weak plants or no plants at all. When large enough to handle, prick the seedlings out into individual pots and grow them on until they are 20cm or more tall before planting them out in their permanent positions. Layering, which takes about 12 months, is successful with most species in this genus. Cuttings of young shoots in June or July. The cuttings should have 2 - 3 pairs of leaves, plus one pair of buds at the base. Remove a very thin slice of bark at the base of the cutting, rooting is improved if a rooting hormone is used. The rooted cuttings must show new growth during the summer before being potted up otherwise they are unlikely to survive the winter. The cuttings of this species usually root easily. Budding onto A. negundo in early summer usually works well. The bud should develop a small shoot in the summer otherwise it is unlikely to survive the winter.
Best place to grow: Woodland Garden Canopy;
Habit: Tree
Hardiness: 3-8
Growth: Fast
Soil: Light (sandy), medium, heavy (clay)
Shade: Semi-shade, no shade
Moisture: Moist
Things to keep in mind
This plant can be weedy or invasive in Northeast USA.