Privet: A Nightmare

Perfectly clipped privet hedges once framed early American homes. It was practical, beautiful, and deeply rooted in tradition. Privet became a go-to plant for living fences across the country. But what was once considered dependable and adaptable has since spread far beyond the garden. In Pennsylvania, several species are now recognized as invasive and prohibited from sale. In our next installment of space invaders, find out how privet became a landscape staple and why its legacy is more complicated than we once thought!

Space Invaders: Privet

Ahh, there’s nothing so heartwarming as the bucolic scenes of an English country cottage, with its chocolate box gardens surrounded by sharply trimmed hedges. Roses, foxgloves, and hollyhocks cheerfully dance in the front garden enclosed with evergreen hedging - anything from boxwood to yew to privet. When English colonists left England and settled in North America, they wished to bring a bit of home with them. As colonial settlements grew and prospered, the land around the home was used not just for growing food but also for displaying beauty. As a way to economically deter wildlife, delineate property lines, increase privacy, and act as a windbreak, colonialists planted hedges, acres and acres of them. Privet was a preferred hedging material - it adapted well to the American climate, grew quickly, and reproduced easily.

Privet (Ligustrum sp.) was originally imported from East Asia in the 1800s as an ornamental plant. Privet is a multi-stemmed, tall, deciduous shrub growing up to 15’ tall with the capacity to sucker. Simple, oppositely arranged bright green leaves cover the grey branches with occasional stems resembling thorns. Soft, creamy white, bell-shaped blossoms cover the shrub in early summer, around May into June. The flowers give way to dark blue-black berries, which birds devour in the fall and winter. Further south, some privet species are evergreen, but in Pennsylvania, they are semi-evergreen. Well-loved by the nursery trade for its adaptability to most soil conditions and light levels, privet was seen as a hardy, tried-and-true shrub for the landscape. It tolerates shearing well, allowing it to be manipulated into many forms. From its broad hardiness (USDA Zones 4-8) to its seasonal appeal and its tough growing capabilities, privet was well-loved for many years. By the 1930s, however, the naturalization of privet into woodlands, fields, and other natural areas was recorded throughout the southeast United States. Now, it is even more widespread. In Pennsylvania, 4 species of privet are of primary concern: common privet (Ligustrum vulgare), Japanese (L. japonicum), Chinese (Ligustrum sinense), and border privet (L. obtusifolium). All 4 species can be difficult to differentiate from each other, and functionally, in the ecosystem and in the landscape, they are treated the same. In Pennsylvania, privet is a USDA-listed noxious weed, prohibited from sale, propagation, or intentional planting within the state.

What’s the problem

To qualify as being listed as a noxious weed by the USDA, a plant has to demonstrate it is found to be injurious to public health, crops, livestock, agricultural land, or other property. Each year, the US spends $21 BILLION annually to manage invasive species. Why is this ornamental shrub so bad?

Privet is fast-growing and adaptable, able to outcompete native plant species in a broad range of conditions, from coastal lowlands to agricultural byways to forest edge. When it gets a foothold, privet shades the forest floor and chokes out native seedlings. Over time, privet creates a monoculture which disrupts the local ecosystem, limiting its ability to function. While not especially flammable on its own, dense stands of privet in the wild can act as “ladder fuel” during drought periods, taking surface fires from the ground layer into the tree canopy and increasing the deadly potential for an accidental fire.

The flowers supply insects with nectar, and the berries support birds in winter; the plant does not support the entire life cycle of wild species as a native fruit-producing shrub would in the same space. The foliage is not a food source for native insects. In large monocultures of privet, birds that depend on caterpillars and insects in spring to feed their young will waste energy searching for caterpillars and find very few. The less food there is for young birds in spring, the fewer native birds we will hear singing in our landscapes.

What to do

Luckily, privet isn’t the worst of invasive species to remove. With solid identification skills, some choice tools, and good timing, one can remove large, established privet stands in a short period. There’s no poisonous sap, mean thorns, irritating foliage, or crazy rhizomes to pull. Winter and early spring are a wonderful time to get out there and do some damage.

Small seedlings or saplings

When the ground is moist from rainfall or snow in winter, go out with a sharp spade and pop those little nuisances from the ground. Get all those roots. There’s nothing as satisfying as clearing out a path of these annoyances, having them stacked up in the garden cart, ready for the fire. It’s easiest to do when the soil has some give - spring and fall are best, but if you’ve had a gentle winter or a rainy summer, there’s no bad time to do it. It just hurts the lower back more when the ground is hard and dry.

Established shrubs

Loppers, hand saws, or a sawzall will do the trick. Cut down all branches to the ground. For those who wish to avoid herbicides, this is when you want to use a good spade or pickaxe to dig up the base of the shrub and the roots. For those with many privet shrubs to remove, apply a systemic herbicide like triclopyr directly to the shrub's fresh wounds to prevent resprouting. Follow the label instructions for dosage, time of year, and application details. The best time to apply herbicide to a fresh wound is when the plant is actively growing, from spring through fall. In winter dormancy, the painted stump will not absorb the herbicide as effectively. Triclopyr is generally a better systemic herbicide for painting cut stems of invasive brush and trees than glyphosate, but if that’s what’s available, it can work.

Mowing?

Mowing with a brush hog or weed whacker to cut down stands of privet can help knock down the plant's top growth. Mowing is especially helpful if you’re trying to get into an overgrown site and need a toehold to begin more intensive management strategies. However, as privet is a hedging plant, it will love that cut back and just come back for more. Mowing is not a stand-alone strategy for privet, but it is effective when used in conjunction with other treatments, such as digging up the roots or applying herbicides.

Burn it with Fire?

Fire is a broad tool and is generally less effective than targeted treatments for individual plants or sizable stands. However, using fire as a management tool for a large landscape as part of its regular maintenance and care will help eliminate opportunistic saplings.

One and Done?

We wish. While physically removing invasive plant material with brush hogs, digging spades, and pick axes, and preventing resprout with herbicide applications are mighty large first steps, they are only one part of a prolonged treatment management plan. Since privet spreads by birds when they consume the berries, as long as stands of privet exist in the surrounding areas, there will be continued invasive plant pressure. Plan to routinely monitor the area and neutralize emerging saplings over time.

What now?

On the list of annoying invasive species to remove, privet hasn’t been the worst offender in our experience. Besides getting whacked in the face with a flailing branch, it generally won’t send you to the hospital (which is how we judge all our invasive plant removal rankings). Its worst quality is its ability to spread far and wide by birds. This means even if you’ve been doing your due diligence in the landscape to eradicate invasive plant material and encourage native species, a happy-go-lucky songbird is about to ruin your afternoon on a fine summer’s day. The work will never be done, but just like doing laundry - if you can get on top of it, the task will be less overwhelming. However, it's one thing if privet came into the landscape by accident. It’s another when someone needs a good hedge or a flowering, berry-producing evergreen shrub, and now folks are saying you should rip your hedge out. What do we recommend replacing that with? Don’t worry - there’s another plant that will love privet’s old spot. Even though we’re perennial growers, here’s our two cents to get started once the privet is gone:

Evergreen native shrub swap-outs:

Yaupon holly Ilex vomitoria

Eastern red cedar Juniperus virginiana

Coastal doghobble Leucothoe axillaris

Mountain laurel Kalmia latifolia

Evergreen native shrubs that can take hedging:

Southern bayberry Morellia cerifera

Northern bayberry Myrica pensylvanica

Inkberry holly Ilex glabra

American holly Ilex opaca

 

Noninvasive evergreen shrubs:

Yew Taxus baccata

Boxwood Buxus sp

 

White flowering deciduous native shrubs or small trees with berries:

Grey dogwood Cornus racemosa or C. sericea

Serviceberry Amelanchier sp.

Elderberry Sambucus canadensis

Viburnum Viburnum dentatum or V. nudum

Blueberry Vaccinium sp.

Fringe tree Chionanthus virginicus

Chokeberry Aronia arbutifolia

Devil’s walking stick Aralia spinosa

 

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