Winterberry, A Beautiful, Multi-Use Native Plant

Barb Mrgich
Adams County Master Gardener

(9/28) Winterberry, (ital)Ilex verticillata(end ital), is a great plant to consider for wet areas, rain gardens, or normal soil. It is a native plant of North America that naturally occurs in wet areas and along stream banks. It will grow in full sun or part shade, but generally will produce more berries in a sunny spot.

For those of us who garden in suburbia, Winterberry offers great versatility. It will tolerate our clay soils of Adams County with no problem. If you are plagued with constantly wet, boggy soil, winterberry is one of the few shrubs that will not only survive, but flourish. Although it prefers wet to damp growing areas, it will also do fine in normal garden soil. Mine has not complained through this summer of heat and drought. It does demand a soil of about 6.8 or lower acidity (pH).

Regarding soil acidity, if your soil pH is much higher than 7.0, the shrub will often develop chlorotic (yellow) leaves. Use a pH litmus test to determine the natural acidity of your soil, then, if needed, add sulphur to lower the number. The natural pH of the soil can never be changed permanently. If you choose to plant this shrub in fairly alkaline soil, be prepared to adjust the pH annually.

Unlike many ornamental shrubs, Winterberry is not grown for its spring flowers or its fall color, but for its bright red berries. The berries appear in late summer. During the early fall, the shrub is beautiful with nice green leaves and bright red berries. Then, after the leaves fall, the berries persist. At least 48 different species of birds enjoy feasting on the berries, but they don’t usually eat them until they soften up after they have been frozen and thawed a couple times. In the meantime, we get to enjoy the red color, winter interest, and added beauty to our winter landscape and decorations.

The word (ital)Ilex(end ital) tells us that winterberry is a holly. Most hollies are evergreen, but winterberry holly is deciduous, meaning that it loses all its leaves in the fall. This allows the bright red berries to shine on bare stems. Also, like all hollies, winterberry is dioecious. Dioecious means that male and female parts grow on separate plants. When you buy winterberry, you need to know if you are buying a female or male. The male must be planted somewhere within about 50 feet of the female. One male can pollinate as many as ten females. Both plants will produce small, white flowers in the spring that you may barely notice. Only the females will get berries.

The straight species of winterberry typically grows anywhere from five to fifteen feet tall. However, there are cultivars available which offer smaller sizes. Many proponents of native plants feel strongly that only the straight species of any native plant should be used, while most nurseries will offer only the cultivars. (Cultivars are variations of the species that offer some features such as different color or size selections). Whether cultivars are good or bad is a debatable topic.

If you are interested in providing wildlife habitat you need to be careful of cultivars that may make it more difficult for the wildlife. Some examples would be double flowers that block pollinators from reaching the pollen, reduced pollen, or berries that are too big for the birds to handle. When purchasing your Winterberry, Penn State Master Gardeners encourage you to look for a nursery that specializes in native plants – or better yet in this case, native hollies. An internet search should help you locate several in Central Pennsylvania. Whichever you choose, it is important to get the correct male that will bloom at the same time as the female. Any reputable nursery will explain these things and direct you to the correct male plant.

The year I bought our shrubs, I planted them in the fall. That winter was especially wet and cold. Through much of the winter, those newly planted shrubs stood in frozen water. I was truly amazed to see them leaf out in the spring, but they were very much alive and healthy!

They were quite small. In the couple years they have been growing, they are still small shrubs as you can see in the picture. There is still a fair amount of bare soil left between them. They are in a swale where water collects with each heavy rain. To prevent erosion, I added the ground cover, Golden Ragwort (ital)(Packera aurea)(end ital), another native plant. This plant has spread itself very quickly covering the bare area nicely. It’s rather large leaves shade the soil to block weeds, and its roots keep the soil in place. In the early spring, it sends up tall stems that produce long-lasting yellow flowers. This year it bloomed for the entire month of May. The only maintenance it requires is to cut off the dead flower stems after it blooms (for aesthetic purposes only).

If you are going to prune winterberries, you should do it in late winter or very early spring. Pruning can promote health of the plant, and encourage uniform shape. Look for the oldest canes, and cut them right down to the ground. Never take out more than 1/3 of the canes in one year. Cut inward growing branches back to the main stem, and always remove any diseased or dead parts back to healthy wood.

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