Thorny elaeagnus

Identification and origin

Elaeagnus pungens belongs to the oleaster family, Elaeagnaceae. It is native to south-central and southeastern China, Korea, Japan and Tajikistan. Planted for hedges, it has escaped from gardens in the southeastern United States, Great Britain, France, Italy, Spain and Mauritius.

It is a dense, spreading, arching evergreen shrub with a fast growth rate. Its height and spread usually reach 13–26 ft in ten to twenty years. Its long shoots head off in all directions and make it look unkempt if left unpruned; thanks to them, it can even climb into nearby trees.

The stems are covered in small brown scales and carry thorns 2–3 in long, which give the plant its name and let it hook onto supports. The alternate, simple, leathery leaves are about 2–4 in long. Ovate to narrowly ovate, they have wavy margins, a glossy green upper side and a silvery underside dotted with tiny brown scales.

In fall, small bell-shaped flowers under 1 in long, silvery white to cream and very fragrant, open in the leaf axils. They are followed by fruit about 1 in long, green and scaly at first, that ripens the following spring to reddish brown or silvery red; birds eat it.

Several cultivars exist: ‘Variegata’, with dark green leaves narrowly edged in creamy yellow, more compact at 5–8 ft tall; ‘Fruitlandii’, with fragrant creamy white flowers; and ‘Hosoba-fukurin’, with narrow leaves margined in cream or light yellow.

Light

It grows in full sun or partial shade, facing any direction. It tolerates shade, but its foliage becomes thinner there. In a container, give it at least four to six hours of sun a day; in a very hot climate, protect it from intense midday sun, which can scorch the leaves.

It tolerates windy, exposed sites, which makes it a good windbreak hedge, especially by the sea.

Watering

In the ground, thorny elaeagnus is drought tolerant once established, and it accepts soils that are occasionally dry or occasionally wet, as long as they drain well. Water mainly during the first year, as soon as the soil surface dries, to help the roots establish.

In a container, check the moisture before each watering: water when the surface is dry, until water drains freely from the bottom, then let it dry slightly before the next watering. Needs increase during the growing season, especially in sun; in winter, water less, without letting the root ball dry out completely. Soggy mix encourages root rot.

Potting mix

Very adaptable, it grows in clay, loam, sand or rocky soil, even poor soil, and accepts acidic, neutral or alkaline pH. One exception: on shallow chalky soil, its leaves can yellow from chlorosis. It is remarkably salt tolerant.

In a container, use a free-draining mix.

Temperature

It suits USDA zones 7a to 9b. In the ground, it stays hardy even through severe winters, down to about 5–14 °F.

In a container, its roots are more exposed to cold: in cold regions, shelter it in a cold frame or an unheated greenhouse during hard freezes.

Repotting

In the ground it does not need to be moved; it is mostly used as a hedge or screen.

In a container, repot every two or three years, or as soon as roots fill the pot, in early spring, just before growth resumes. Shorten overly long or damaged roots and replace the mix. Water thoroughly, then keep the plant sheltered from strong wind and direct sun for a few weeks while it settles in.

During the growing season, from early spring to fall, a balanced solid organic fertilizer every four to six weeks is enough, applied to moist mix. Stop in winter. Overfeeding produces lots of leaves and weak branches.

Pruning

It takes pruning very well, even hard pruning, and works as a clipped hedge. Keep in mind, though, that next year’s flowers form on old wood: pruning too hard reduces the fragrant fall bloom.

Shorten long shoots regularly to keep a compact habit and stop the shrub from climbing into its neighbors. Remove suckers from the base if needed, preferably in fall. On variegated forms, cut out any shoots that have reverted to plain green.

Propagation

Semi-hardwood cuttings are the most common method, in summer or into early fall: take stems 4–6 in long, strip the lower leaves, dip the base in rooting hormone and insert them in a free-draining mix of sand and peat, kept humid and in indirect light. Rooting takes from a few weeks to a few months.

Layering also works: lightly wound a low branch and bury it so it roots. The species also self-seeds, which explains its spread in the wild.

Common problems

• Discolored, stippled leaves, fine webbing: spider mites, especially on a stressed plant.
• Sticky residue on the leaves: aphids, elaeagnus psyllid or scale.
• Spots on the leaves: fungal leaf spot or rust.
• White felt: powdery mildew, encouraged by stagnant air.
• Dying shoots: coral spot.
• General decline: root rot from overwatering, or honey fungus.

In the southeastern United States it is listed as invasive: it forms thickets, crowds out native plants and spreads by seed and suckers. Avoid planting it near natural areas where it is a problem. A symptom can have several causes: always check watering and exposure before treating.

Toxicity

No toxicity reported: veterinary references list elaeagnus as non-toxic to dogs, cats and horses. The thorns can injure, however: wear gloves when pruning.