Elaeagnus or eleagnus, is a genus of over 50 recognized species of flowering, ornamental shrubs. This plant commonly grows in gardens in the Northern Hemisphere, in America, and in Asia.
These perennial shrubs, also known as the silverberry, are grown as ornamental trees to create a windbreak or hedge. There are both deciduous and evergreen varieties of eleagnus.
The genus was first categorized by Carl Linnaeus. There is agreement that the first part of the name “elaea” is derived from the ancient Greek “olive” and refers to the name of the shrub.
However, there are several theories as to the derivation and meaning of the second part of the name, including “chaste”, “pure”, and “willow”.
There are 54 species of the silverberry (Eleagnus) genus dispersed in the Qinghai-TIbet plateau in Asia. It is known, from fossil research and records, that this genus was present in Tibet during the Miocene age (at least 5.3 million years ago).
There are several species of Elaeagnus that are now listed in the Plant Database as invasive. Due to their popularity as garden ornamentals, more cultivars are still being developed each year.
Eleagnus species were first introduced into North America in the early 1800s, and into Europe at around the same time. Originally, native to Asia, there were brought to America because they were considered beneficial.
The fruit was a food source for wildlife, the shrubs were a good choice for erosion control, and they were a low-maintenance plant that could be used to restore land spoiled by drift mining exploitation.
Considerably later, eleagnus shrubs found their way to New Zealand and to Israel, but exactly when is not known.
Unfortunately, various species of eleagnus outcompete native vegetation. They shade plants growing underneath their branches.
The thorny varieties can climb and block sunlight from larger shrubs. Three species, in particular, are considered invasive: E. umbellata, E. angustifolia and E. pungens.
|Scientific name||Eleagnus, Elaeagnus|
|Common names||Silverberry, Oleaster, Eleagnus|
|Height||Usually about 12 feet (3.66 m)|
|Width||Usually about 12 feet (3.66 m)|
|USDA Plant Hardiness Zone||Zones 7 to 9|
|Native to||Parts of Australia, Asia, North America, Europe|
|Plant specific features||Tolerant of salt, a good windbreak for a coastal location, nitrogen-fixing shrub|
How to Plant and Grow an Elaeagnus Bush
Eleagnus is an easy-to-grow shrub, that is hardy and well-suited to colder climates. It will grow in coastal regions and tolerates pollution.
The planting hole should be two or three times larger than the diameter of the plant’s root ball. Do not plant the shrub deeper than it sits in the container.
Where to Plant
Due to its saline tolerance, eleagnus is a useful shrub to grow in exposed coastal locations. Equally, it can grow along roadsides, since it copes with pollution in the atmosphere.
Elaeagnus is often chosen as a hedging plant, or to create a windbreak. It is a hardy shrub and an evergreen variety makes an excellent, dense screen or hedge.
Eleagnus is a shrub that doesn’t like to be replanted, so if possible, select the planting site with care so that it won’t need to be disturbed.
When to Plant
If you are planting in a cooler climatic region, that will experience frosts and cold winter weather, then the best time to plant an eleagnus shrub is in the Spring. Make sure it is after the last frost, though!
In warmer regions, where snow and frost are rare and short-lived, then you can plant in the fall.
Elaeagnus Shrubs Care and Maintenance
Elaeagnus will thrive in any fertile soil and tolerates chalk as well as clay soils. The soil needs to be well-drained or there is a risk that the roots of the shrub will rot.
Because elaeagnus shrubs are nitrogen-fixing, they will thrive in poor soil, because they can use this process to improve the soil available to their root system.
Eleagnus can be grown in soil that is acidic, neutral, or alkaline.
One of the many benefits of planting elaegnus shrubs is that they are low-maintenance plants. They tolerate dry conditions. Watering requirements, once the plants are established, are low.
Like all newly planted shrubs, it is important that regular watering is given. This enables the shrubs to develop strong root systems so that they will be better equipped to deal with dry spells later on.
Watering thoroughly and less frequently is preferable because this will encourage the plant to develop a deep root system, enabling it to access moisture from deeper in the ground.
Nitrogen-fixing plants, such as the eleagnus, contain chemicals on their roots that can absorb and store nitrogen. This nitrogen remains available exclusively to the host plant (in this case, the eleagnus) and neighboring plants are unable to draw on it unless the host plant dies.
Elaeagnus likes open and sunny conditions, but it isn’t a fussy shrub. It will still thrive in partial shade.
Pruning and Repotting
Always keep your shrub free of dead, diseased, or decayed wood. This will help to prevent disease and pests from attacking your plant. You can remove dead branches as soon as you notice them, at any time of year.
More deliberate pruning should be carried out in the spring. This can involve trimming the shrub’s branches and the top of the hedges.
However, elaegnus will not appreciate having too much old wood removed. If the shrub has been neglected, prune it back over a couple of years to minimize stressing the plant.
If you notice that there are plain green shoots growing on a variegated plant, it is important to remove them promptly. Failure to do so can result in the shrub reverting to an all-green plant, and you will lose the variegation.
The best and most usual method to propagate evergreen elaeagnus is by taking semi-ripe cuttings in the summer. But you can also take hardwood cuttings just before the winter and overwinter them in a cold frame or unheated greenhouse.
Sometimes, you will be able to dig up rooted suckers and transplant them into the garden.
Deciduous varieties can also be propagated from seed. Collect the seed from the fruits, and keep them cool and dry until it is time to sow them in the early Spring. If, however, you are attempting to propagate a hybrid from seed, the seedlings are unlikely to be the same as the parent plant.
And the seeds may be sterile, meaning that they will not germinate at all. For more reliability, it is usually best to propagate from cuttings.
Pests and diseases
When planted in poorly draining or wet soil, the eleagnus shrub can suffer from excess humidity. This can lead to various fungal pathogens attacking the plants, resulting in diseases such as Verticillium wilt.
The eleagnus will wilt, its leaves will become discolored, and drop and the plant’s branches will die back. Once this fungal disease has a hold on the plant, there is no cure. Fungicides won’t work.
Leaf spot is another fungal disease, but this is less serious, and will probably only result in cosmetic leaf damage. The leaves discolor and turn brown or gray. The foliage may drop prematurely.
Often, it is not necessary to treat leaf spots. Once damp weather is replaced by warmer, drier conditions, air humidity will reduce and the problem will go away by itself.
You can help to prevent the spread of fungal disease by keeping your shrub in good health. Destroy any infected foliage, and keep the base of the plant free from weeds and damp material.
Once a year, prune out from the center of the shrub to improve air circulation around the plant.
Eleagnus is deer resistant.
Temperature and Humidity
All varieties of elaeagnus tolerate heat and survive the cold once they are established. They also have wind and drought tolerance.
A mature eleagnus shrub will survive temperatures as low as -40 °C. However, unripe wood will die back during cold winters if they have not had sufficient time and exposure to summer temperatures.
Humidity is not normally a concern with eleagnus. But it prefers well-drained soil and if subjected to excess humidity, minor health issues may arise.
Other Uses for Eleagnus
Commonly grown as a hedge and privacy screen, the salt and wind tolerance of the eleagnus makes it a useful choice for coastal gardens.
There are many reports of the fiber and bark of eleagnus being used for craft purposes. The bark has been used to produce strong cord and rope, woven into blankets and clothing. The fruit was dried and made into beads or into an extract for soap production.
For an edible garden too, the eleagnus is a good choice as the fruit has a high food value. Wildlife, in particular certain bird species, also love the fruit.
The fruit is rich in vitamins and minerals and can be eaten raw or cooked. It is tart when raw unless fully ripe, but can be sweetened and used in tarts and pastries.
The fruit can be added to soup, or made into jellies or jams. The fruit contains an edible seed, which is fibrous if eaten.
There are some medicinal uses for eleagnus, including current studies which are being undertaken as to the fruit’s anti-carcinogenic properties.
Types of Eleagnus (Silverberry) You Can Grow
As well as the listed species, there are many cultivars bred and more being introduced each year.
Eleagnus varieties can be deciduous or evergreen. Some species will be evergreen in warmer climates, but lose their leaves in winter in regions with cooler temperatures.
Propagation of eleagnus cultivars includes many plants that have been developed for variegation of foliage and leaf color.
Other forms are bred to be slow or fast-growing; some for increased fruit production and others to be evergreen. Different species and cultivars grow as compact shrubs, whilst others will grow into large single-stemmed trees.
Elaeagnus ebbingei is a species from which many cultivars have been borne. This variety keeps its leaves in winter and, in a variegated form, brings golden or silver light to a shady corner of your garden.
Cultivars such as the evergreens “Gilt Edge” or “Limelight” flower during the Autumn, and provide scented creamy-white flowers followed by edible fruit. These varieties are a little less cold-hardy than others (but will still survive -15°C).
“Limelight” has silvery leaves that turn lime green and gold as they mature.
“Gilt Edge” has dark green glossy leaves that are bordered by golden yellow. Their creamy white small flowers are sometimes followed by orange berries.
Elaeagnus umbellata, also known as Autumn olive, is deciduous and bushy. It will grow to around 5m in both height and spread. Its fragrant pale yellow flowers turn into egg-shaped, silver-colored fruit that turn reddish, when ripe.
Elaeagnus umbellata “Sweet ’n’ Tart, also known as Oleaster “Sweet ‘n’ Tart” grows fast and is a deciduous variety. It has narrow leaves, and masses of small, fragrant blooms in early Summer.
Following the flowering period, this eleagnus variety produces red fruit in Autumn that are larger than typical elaeagnus fruit, sweet, acidic, and edible.
Elaeagnus umbellata or Autumn olive, is invasive.
Eleagnus contains some species that are regarded as invasive. This is particularly true in certain regions of North America. Birds are responsible for spreading the distribution of the seeds of the eleagnus shrubs.
However, the eleagnus, or silverberry is a very useful shrub. It has fragrant flowers followed by edible berries. The evergreen foliage of many of the species provides all-year interest.
*image by SaraTM/depositphotos