Holm Oak
Quercus ilex ballota

Family: Fagaceae

What it is like

Quercus ilex ballota is an evergreen Tree growing to 25 m (82ft) by 20 m (65ft) at a slow rate. See above for USDA hardiness. It is hardy to UK zone 7. It is in leaf all year, in flower from May to June, and the seeds ripen from September to 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: light (sandy), 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 moist soil. The plant can tolerate maritime exposure.

Height (m): 25

Where it is found

Arid places, maquis, woods and hills on limestone.

Europe - Mediterranean.

Conservation Status:

Countries/locations it is found in

How it is used

Food

Rating: 5

Seed - raw or cooked. The seed of this variety is normally sweet. The seed is up to 3cm long, it can be dried, ground into a powder and used as a thickening in stews etc or mixed with cereals for making bread. The seed from some trees contains bitter tannins, these can be leached out by thoroughly washing the seed in running water though many minerals will also be lost. Either the whole seed can be used or the seed can be dried and ground it into a powder. It can take several days or even weeks to properly leach whole seeds, one method was to wrap them in a cloth bag and place them in a stream. Leaching the powder is quicker. A simple taste test can tell when the tannin has been leached. 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. An edible oil is obtained from the seed.

Oil: Oil

Seed: includes nuts, cereals, peas and beans.

Coffee: the various substitutes that can be used instead of coffee.

Medicine

Rating: 2

Any galls produced on the tree are strongly astringent and can be used in the treatment of haemorrhages, chronic diarrhoea, dysentery etc.

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.

Other

Rating: 3

A mulch of the leaves repels slugs, grubs etc, though fresh leaves should not be used as these can 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. Very tolerant of maritime exposure and of trimming, it can be grown as a shelterbelt tree or hedge in maritime areas. Wood - strong, hard, durable. Used for furniture. It makes a good charcoal and a good fuel, burning well even if green. The bark is a source of tannin.

Fuel: Usually wood, plant materials that have been mentioned as being a good fuel.

Hedge: Plants that can be grown as hedges.

Oil: Vegetable oils have many uses, as lubricants, lighting, soap and paint making, waterproofing etc. This does not include the edible oils unless they are also mentioned as having other uses.

Repellent: Plants that are said to deter but not necessarily kill various mammals, birds, insects etc.

Shelterbelt: Wind resistant plants than can be grown to provide shelter in the garden 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.

Hedge: Hedge

How it is grown

Prefers a good deep fertile loam which can be on the stiff side. Thrives on shallow chalky soils. Succeeds in all soils except those that are cold and poorly drained. Grows well in sandy soils. Young plants tolerate reasonable levels of side shade. Very resistant to maritime exposure. A very ornamental though quite slow-growing tree. Transplants badly unless moved regularly and this should be done as growth commences in late May or in September. This plant is treated as a distinct species, Q. rotundifolia. Lam. by some botanists. Cultivated for its edible seed in Spain. The tree grows well in Britain but is said to fruit poorly here, however a tree at Kew was bearing a very good crop at the end of the hot summer of 1989 and again in 1991. The seed ripens in its first year. Hybridizes freely with other members of the genus. This species is notably resistant to honey fungus.

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; Hedge;

Habit: Tree

Hardiness: 6-9

Growth: Slow

Soil: Light (sandy), medium, heavy (clay)

Shade: Semi-shade, no shade

Moisture: Moist

Things to keep in mind

Its other names

Local names

Synonyms

Q. ballota. Q. rotundifolia.