Meet the Olives that are not really Olives – A thorny Issue
If you live on the Northern Neck, but are not involved with the Native Plant Society or Master Naturalists you may not know that there are three so named olive trees/shrubs that are prevalent here; Russian Olive, Autumn Olive and Thorny Olive.
They are not true olives but are members of the Oleaster family. They were named because the shape of their tiny fruits resemble the edible fruit of true olives. These plants are found all along our roads, in our natural heritage sites, in our historic sites, in our national and state forests, in municipal communities and sadly, part of the landscapes of far too many private properties. All three of them are highly invasive and cause damage to the habitat of the Northern Neck by spreading rapidly, forming dense colonies and replacing important native vegetation.
Autumn Olive, Elaeagnus umbellata, is the most common and has been here the longest. It was introduced in the 1830s to revegetate mine spoils, and was popular as a windbreak and an ornamental. However, because of its high and tasty fruit production, it quickly spread by birds into open woods, fields, road ways and along beaches and waterways. There are few areas that it finds inhospitable. It forms dense thickets, displaces native vegetation and prevents the growth and regeneration of native plants.
Russian Olive, Elaeagnus angustifolia, was introduced in the late 1800s as an ornamental and is highly invasive in California and at least 16 other western states. Like so many non-natives it is pest free, easy to grow and appears to be an attractive landscaping plant until it matures and begins to flower and fruit. According to The California Department of Fish and Wildlife, ”Russian olive escapes cultivation easily, especially along riparian zones. When Russian olive establishes in an area, it chokes out native plants and prevents them from re-establishing, and can be detrimental to the natural hydrology of riparian areas such as stream banks.” It has become more prevalent on the Northern Neck because it has been sold by landscapers for new construction to help define property lines.
Thorny Olive, Elaeagnus pungens, is a dense evergreen shrub that has invaded natural areas throughout the southeastern United States. The shrub is often multi-stemmed and short. Sharp shoots give it a thorny appearance. Shrubs can grow 3.3-26.3 ft. (1-8 m) tall. They are usually very dense with long shoots extending from the top. While not as common in the Northern Neck, it is here and where it has been allowed to take over, is the most intimidating to manage of the three because it forms impenetrable thorny thickets.
Each of these trees/shrubs have specific characteristics that help differentiate them, but the common characteristic they share and which makes them easy to identify is the silver color on the underside of their leaves. It is quite dramatic and obvious when the wind is blowing and the leaves appear to change from green to silver.
It is important that efforts be made to remove and control these invasives using the correct management strategies. While periodic removal projects are planned at Belle Isle, Rappahannock River Wildlife Refuge, Stratford Hall, George Washington’s Birthplace, and the Natural Heritage Sites on the Northern Neck, these areas will continue to be invaded as long as private landowners have these plants as part of their landscape. Northern Neck PRISM (Partners for Regional Invasive Species Management) encourages all landowners to take the following steps.
- Survey your property and identify these plants. There are several excellent Plant ID apps available for free that will help you identify what is on your property.
- Get Fact Sheets on Identification and Management. These are available on line from Blue Ridge PRISM and Department of Conservation and Recreation. Fact sheets are also available at NNVNPS/NN PRISM
- Do not purchase these plants for your landscape. Many invasive plants are available for sale through big box stores, smaller plant stores, and landscaping businesses. Landscapers are now mandated by law to inform landowners when they include invasives as part of a landscaping plan. However, the responsibility ultimately resides with the homeowners to know what is being planted on their property.
- Manage olives on your property. Information on removal and management is available on the fact sheets and very important to follow. These invasive plants are controllable through a combination of mechanical and chemical strategies. Unfortunately, like almost all weeds, they will grow back, but persistent oversite will result in eventual eradication.