Burr Oak, Mossy Cup Oak
Quercus macrocarpa
Family: Fagaceae
What it is like
Bloom Color: Brown. Main Bloom Time: Early spring, Late spring, Mid spring. Form: Rounded, Spreading or horizontal.
Quercus macrocarpa is a deciduous Tree growing to 15 m (49ft) by 8 m (26ft) at a slow rate. See above for USDA hardiness. It is hardy to UK zone 3 and is not frost tender. It is in flower in May, and the seeds ripen in October. The species is monoecious (individual flowers are either male or female, but both sexes can be found on the same plant) and is pollinated by Wind. Suitable for: medium (loamy) and heavy (clay) soils 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 dry or moist soil and can tolerate drought. The plant can tolerates strong winds but not maritime exposure. It can tolerate atmospheric pollution.
Height (m): 15
Where it is found
Found in a variety of habitats from dry hillsides to moist bottomlands, rich woods and fertile slopes, mainly on limestone soils.
Eastern N. America - Nova Scotia to Manitoba, Wyoming, Massachusetts, Georgia, Kansas and Texas.
Conservation Status:
Countries/locations it is found in
How it is used
Food
Rating: 3
Seed - cooked. Very large, the seed can be up to 5cm x 4cm, though it is somewhat variable in size and shape. The seed can be ground into a powder and used in making bread, dumplings etc and as a thickener in soups. The seed of this species is considered to be one of the most palatable of all the oaks. Many trees have sweet seeds with little tannin and the seed can be eaten raw or cooked. If the seed is bitter then this is due to the presence of tannins, these can be leached out by thoroughly washing the dried and ground up seed in water, though many minerals will also be lost. The traditional method of preparing the seed was to bury it in boggy ground overwinter. The germinating seed was dug up in the spring when it would have lost most of its astringency. The roasted seed is a coffee substitute.
Seed: includes nuts, cereals, peas and beans.
Medicine
Rating: 2
The bark is astringent and tonic. An infusion has been used in the treatment of diarrhoea. A decoction of the root or inner bark has been used in the treatment of cramps. Any galls produced on the tree are strongly astringent and can be used in the treatment of haemorrhages, chronic diarrhoea, dysentery etc.
Antispasmodic: Relaxes muscular spasms and cramps, calming nervous irritation.
Astringent: Produces contraction in living tissue, reducing the flow of secretions and discharges of blood, mucus, diarrhoea etc.
Dysentery: Used in treating dysentery - an infection of the intestines that causes diarrhoea containing blood or mucus.
Tonic: Improves general health. Slower acting than a stimulant, it brings steady improvement.
Other
Rating: 4
Agroforestry Uses: The tree has been widely tested for use in rehabilitation of the soil. It has been successfully planted on coal spoils in the north-central and northern Great Plains, and in the Western Interior Coal Province which encompasses Missouri, Kansas, and Oklahoma. It may be either seeded or transplanted onto disturbed areas. Other Uses: The leaves of most species in this genus are more or less rich in tannins. A mulch of the leaves can be placed around vulnerable plants in order to repel slugs, snails, grubs etc. Fresh leaves should be used with caution, since these can utilize some of the nitrogen in the soil and this inhibit plant growth. Oak galls are excrescences that are sometimes produced in great numbers on the tree and are caused by the activity of the larvae of different insects. The insects live inside these galls, obtaining their nutrient therein. When the insect pupates and leaves, the gall can be used as a rich source of tannin, that can also be used as a dyestuff. The bark has been used as a mordant for fixing dyes. The wood is hard, heavy, strong, tough, very durable, close grained. It weighs about 46lb per cubic metre. This species is of considerable importance as a timber tree, it is used for all types of construction, in making baskets, flooring, cabinet making, ship building, cooperagem fence posts etc. The wood is a good fuel.
Mordant: Used for making a dye more permanent, it also affects the colour of the dye.
Repellent: Plants that are said to deter but not necessarily kill various mammals, birds, insects etc.
Tannin: An astringent substance obtaied from plants, it is used medicinally, as a dye and mordant, stabilizer in pesticide etc.
Wood: A list of the trees and shrubs that are noted for having useful wood.
Food Forest: Plants for Edible Forest Gardens and Food Forests.
How it is grown
Landscape Uses:Firewood, Pest tolerant, Aggressive surface roots possible, Specimen. Prefers a good deep fertile loam which can be on the stiff side. Lime tolerant. Succeeds in a hot dry position. Young plants tolerate reasonable levels of side shade. Tolerates moderate exposure, surviving well but being somewhat stunted. A slow-growing tree. Established plants are drought resistant and tolerant of atmospheric pollution. Trees have a thick, fire-resistant bark. Occasionally cultivated for its edible seed, there are some named varieties. Slow growing in the wild, it takes about 30 years to start producing seed, though it then continues to crop for the next 200 - 300 years with large crops being produced every 2 - 3 years. The tree flowers on new growth produced in spring, the seed ripening in its first year. Prefers warmer summers than are usually experienced in Britain, often growing poorly in this country and failing to properly ripen its wood, resulting in frost damage overwinter. A tree at the Hillier Arboretum in Hampshire was growing well in September 1993. It was 9 metres tall but had a lot of mildew, there was no sign of seeds. There is a dwarf form of this species: Q. macrocarpa depressa (Nutt.)Engelm. grows about 2 metres tall with corky branches and smaller seeds than the species, usually about 1cm long. Hybridizes freely with other members of the genus. Plants in this genus are notably resistant to honey fungus. Special Features:North American native, Inconspicuous flowers or blooms. The plant is heat tolerant in zones 9 through 1. (Plant Hardiness Zones show how well plants withstand cold winter temperatures. Plant Heat Zones show when plants would start suffering from the heat. The Plant Heat Zone map is based on the number of "heat days" experienced in a given area where the temperature climbs to over 86 degrees F (30°C). At this temperature, many plants begin to suffer physiological damage. Heat Zones range from 1 (no heat days) to 12 (210 or more heat days). For example Heat Zone. 11-1 indicates that the plant is heat tolerant in zones 11 through 1.) For polyculture design as well as the above-ground architecture (form - tree, shrub etc. and size shown above) information on the habit and root pattern is also useful and given here if available. The plant growth habit is a standard with a non-suckering single trunk. The root pattern is a tap root similar to a carrot going directly down.
Propagating it: Seed - it quickly loses viability if it is allowed to dry out. It can be stored moist and cool overwinter but is best sown as soon as it is ripe in an outdoor seed bed, though it must be protected from mice, squirrels etc. Small quantities of seed can be sown in deep pots in a cold frame. Plants produce a deep taproot and need to be planted out into their permanent positions as soon as possible, in fact seed sown in situ will produce the best trees. Trees should not be left in a nursery bed for more than 2 growing seasons without being moved or they will transplant very badly.
Best place to grow: Woodland Garden Canopy;
Habit: Tree
Hardiness: 3-8
Growth: Slow
Soil: Medium, heavy (clay)
Shade: Semi-shade, no shade
Moisture: Dry, moist