Tidewater Gardening - November 2008

Sexing Up Your Holly

by

K. Marc Teffeau

   For gardeners, November is a transition month, moving from fall into winter. The foliage color display is just about finished and the rains in October and early November have removed most of the leaves from the trees. It is at this time of year that the various hues of greens and blues of the narrow and broad-leafed evergreens start to stand out in the landscape. The clear, cool November days are and excellent time to prepare the landscape and garden for the winter months.
    Every year, a number of homeowners complain that their holly trees do not have berries. Hollies are dioecious plants, which means that each sex is confined to a separate plant. Therefore, to have berries on the “Harriett” holly, you need a “Harry” holly somewhere nearby. Most of the time the failure of a mature female holly to fruit is because of lack of pollination.
    The only solution to this problem is to either replace the male plant with a female of the species, or by transplanting a male plant nearby to insure pollination of the female flowers. It is important that there be a male plant within 500 feet to insure good pollination. The only time you can determine the sex of a holly is when it is in bloom, and even then it can be difficult.
    Another plant whose fruit display in the fall can be beautiful is the firethorn (pyracantha). However, some of you might have noticed that your firethorn is not fruiting heavily as your neighbors. This is a common problem, but it is not easily solved without sacrificing something.
    Most firethorns, when planted in full sun and in a well drained soil, will flower and fruit regularly with little care. However, as other plants begin to shade them, there can be a significant reduction in the numbers of flowers and fruits produced. If you have a firethorn that was once a heavy producer of fruit, look at it carefully on a sunny day to see how much shade it is receiving. Try to correct the situation by pruning other nearby plants to let the firethorn have more sun. It usually pays off in that the plant will again produce more berries.
    Contrary to many homeowner beliefs, fertilizers will have little effect on increasing fruit production of a firethorn that is in the shade. Often, over-fertilization will result in increased susceptibility to fire blight, which is a bacterial disease that often kills the entire plant. So don’t try to fertilize pyracantha too heavily. If you do want to fertilize, use a material that is low in nitrogen and higher in phosphorus and potassium.
    The cultural requirements for firethorns are similar to those of holly. They prefer to grow in full sun in a well drained soil with a pH between 5.5 and 7.5. I recommend planting them in the spring using a container-grown plant. Because of their coarse, poorly-branched root system, it is almost impossible to dig these plants with a ball of soil around the roots. Choose your location carefully as they are very difficult to transplant.
    There are some excellent cultivars of firethorns available that do well in our area. “Apache” is a semi-evergreen compact shrub with bright red fruits that ripen in September and persist until December. “Navaho” is a low-growing, densely branched, mounded type with rich orange-red fruits and “Shawnee” produces bright yellow-orange berries that last until late winter. All these cultivars are resistant to scab and fire blight, the two major disease problems in firethorns.
    Pyracanthas tend to get ratty in appearance over time so it is important to do selective pruning. The yearly spring removal of vigorous growing branches will help keep this plant compact. Prune with the natural shape of the plant in mind. Don’t prune them into squares, balls, triangles or other assorted shapes! Leave the topiary pruning to the experts.
    As you clean up around the landscape this month, you might see turf areas that are thinning out and haven’t recovered from the dry summer. If these areas are slightly shaded, you might consider replacing the turf with a ground cover like ivy. I know, English ivy is getting a bad rap in some circles as an invasive plant, and in some plantings, especially adjacent to wooded areas, it has become a problem. But the point is, the right plant in the right place. In many of our home landscape situations in suburbia and commercial landscapes, ivies have a place.
    A variegated ivy that you might want to consider is the American Ivy Society’s Ivy of the Year for 2008, Hedera helix ‘Gold Child.’ This beautiful gold variegated ivy was originally introduced in England in 1971 and first appeared in the U.S. in the early 1980s where it quickly became popular with commercial growers.
    According to the American Ivy Society, Gold Child’s leaves have three to five lobes with rounded tips. The variegation is a bright gold margin with a green to green-gray center. The brightness of the variegation is temperature-dependent. In cooler temperatures the color is a very intense gold, but in warmer weather the color can fade to butter yellow. The color is also not as intense if grown in the shade, the variegation is still prominent.
    The Ivy Society recommends planting ivies deep, removing several of the lower leaves, and planting to the new lowest leaves. Ivies will root along this new stem, allowing the ivy to better establish into the new planting. When possible, especially with variegated ivies, plant them where they will be protected from the winter sun and wind which causes the most winter damage.
    November is the best time to mulch your strawberry bed. After the first or second hard frost, apply a mulch such as weed-free straw, chopped corn stalks, ground corn cobs, bark chips or pine needles. Apply it so that when it settles it is no more than two inches deep. Be careful not to smother the crowns of the plants.
    A light layer of mulch protects plants from severe winter temperatures. It also helps keep soil at an even temperature which prevents the alternate freezing and thawing of the soil. This temperature change can cause the strawberry plants to “heave” out of the soil, resulting in crown and root death. Mulching is especially important where plants are being grown through a black polyethylene covering.
    If you delay removal of the mulch in the spring, the plants will remain dormant later into the season. This often delays blossoming past the critical frost period. In this area, you can remove the mulch in early or mid April if it is a normal spring.
    As soon as chrysanthemums are through flowering, remove the stalks to within a few inches of the ground. This will help root development and make plants send out vigorous sprouts in the spring. Some may be lifted and heeled into the cold frame. Plants for potting can be propagated from the side sprouts that will develop next May. Dispose of stems and all dropped and dried leaves and branches. Apply a 2- to 3-inch layer of loose mulch, such as leaves, after the ground has frozen.
    Happy gardening!!!