Tidewater Gardening January 2011


Woody Plant Winners for 2011
K. Marc Teffeau


Usually in January I like to highlight the Pennsylvania Horticultural Society winners and their Gold Medal Plant Awards for the new year. The PHS has conducted the Gold Medal Plant program since 1979 and usually have some great woody plant selections that will grow very well in our area. For 2011 there are three native cultivars to the eastern United States, the fourth is a tough shrub from Europe which has great winter interest.
For 2011 a native honeysuckle is on the list. No, don’t worry, it is not the notorious Japanese species that takes over everything! Diervilla sessilifolia Cool Splash ‘LPDC Podaras’ (Southern Bush Honeysuckle) is native to the southeastern United States and is a low-growing deciduous shrub. Vigorous and adaptable, it spreads by suckers into a reliable mass. Cool Splash tolerates all light conditions but performs best in full sun. Its variegated glossy leaves develop vivid tones of green and cream.
While visiting Dr. Harold Pellet at his Landscape Plant Development Center (www.landscapecenter.org) in Aurora, Oregon, a couple of years ago, he pointed out the plant to me and discussed its characteristics. The plant was introduced in 2009 by Bailey Nurseries in Minnesota. Originally developed out of Dr. Pellet’s plant breeding program in cooperation with Cornell University, the plant has small yellow flowers that form on new wood which cluster from June to August. Perfect for massing or the perennial border, it grows 2½ feet high and 3½ feet wide and benefits from a moderate spring pruning.
When I say “sweet gum” you usually think of the prickly gum ball fruits. The fruit, a ready source of missiles to be thrown by kids and a bane to the homeowner, usually does not endear itself to the home landscape. However, I guess that Liquidambar styraciflua ‘Slender Silhouette’ (American Sweetgum) has enough redeeming characteristics for the PHS to put it on their list.
‘Slender Silhouette’ is a very narrow, low-maintenance cultivar of the American sweetgum tree, growing 50 feet high and only 4 feet wide. Unlike the true native species, ‘Slender Silhouette’ produces little fruit (those brown spiky orbs), which when dropped, land in a small, easily cleaned-up area. The tree’s dark green glossy leaves turn yellow with a tinge of red in the fall. This is a great park or allée tree, but you can use it anywhere you need a narrow tree. It prefers moist soil and space for root development.
When I was the county agent for Talbot County many years ago, I remember a call from a homeowner who said that a fly-by-night “arborist” – these are dudes with a pickup truck, a magnetic sign on the door and chain saws in the truck bed – was trying to talk her into cutting down her Bald Cypress tree because it has turned brown and was dead. So much for the alleged tree knowledge of the shyster. Fortunately, the homeowner did not fall for the scam as she knew that the tree was a deciduous conifer.
Bald Cypress is a neat tree in its own right. The PHS’s award winner, Taxodium distichum var. imbricarium Debonair ‘Morris” (Pond Bald Cypress) is a unique tree which carries interesting green pendulous foliage that strikingly contrasts with its formal, pyramidal habit. It exhibits a great bronze fall color and a dramatic winter silhouette.
As with the species, the cultivar flourishes in most landscape situations, especially those with moist soil, but I have seen it do very well in dry sandy locations. The tree grows to 60 feet high and 20 feet wide, so you will need to give it some room to grow.
Blood Twig Dogwoods are a great deciduous shrub in our area that provides excellent winter color to the landscape because of its highly colored bark. The cultivar Cornus sanguinea ‘Midwinter Fire’ is a truly superior winter interest plant. This is a large deciduous shrub which spreads by suckers to form a dense clump, so give it room to grow. It is definitely not a foundation plant as it grows 8 feet high by 10 feet wide.
In the fall, ‘Midwinter Fire’ leaves turn greenish-purple and then drop to reveal spectacular stems that provide an intense display of yellow, orange and red hues from late fall to early spring. The effect is especially spectacular when they are placed in front of a dark backdrop.
To get the best effect, be sure to plant the shrub in a full sun exposure. Hard spring pruning to annually renew the plant and produce new wood will result in the best stem colors. Providing abundant clusters of white flowers in mid May, ‘Midwinter Fire’ looks great in a shrub border, in masses or in containers.
For a complete listing of the PHS winning plants with profiles, pictures and sources, go to www.goldmedalplants.com. Kudos to the Pennsylvania Horticulture Society for offering this program of award winners each year to home gardeners!
Many of us will receive gift plants for Christmas ranging from the traditional poinsettia to more exotic types such as cyclamen and Christmas Cactus. Your holiday plants can continue to provide good cheer well into the new year provided you give them the proper care and attention. You need to remember that Christmas plants have been grown under ideal conditions in greenhouses. Although we cannot duplicate these conditions in the average home, we can still provide for the basic needs of the plants.
The atmosphere in the average home is usually hot and dry, especially if you have a woodstove or forced air heat. This dryness can shorten the life of your plant unless extra humidity is provided. It isn’t easy to increase the humidity in the house but there are a few tricks you can use.
Grouping your plants together helps, along with frequent misting with a spray bottle or setting plants on water-filled pebble trays to raise the humidity. You may also have higher humidity in the kitchen or bathroom.
Proper watering remains a must throughout the winter. But, as a general rule, you’ll need to water less than in the summer because of the normally lower room temperatures, less light and slower plant growth. Remember not to water on a schedule, but on an “as needed” basis.
Your plant should be given plenty of light. Light is always a critical factor for house plants, but it is especially so during the winter months. Be aware of each plant’s light needs and provide accordingly. A sunny windowsill is a good location, but be careful that the foliage doesn’t touch the cold windowpane and get frostbitten. Remember that flowering plants require the most light. When natural light is lacking, you may have to provide more from artificial sources.
We like to keep our homes warm and cozy during wintertime, but sometimes it’s a bit too much for indoor plants. Most do well at normal temperatures (68-72°) during the day, but like it about 10° cooler at night. Back in the 1970’s when we had the “energy crisis,” everybody turned their house temperatures down and the house plants did a whole lot better.
Also, be sure to avoid placing the plants close to heat registers, fireplaces and woodstoves. Conversely, make sure that the plants are not exposed to drafts from around windows, doors or heating vents.
Once you decide on a suitable location for the plant, keep it there. Moving the plant around requires it to readjust to its new environment. Usually, the first sign of a readjustment is that it drops its flowers or leaves.
Because your plants tend to grow less during the winter, they “eat” less. Feed them only when they are making visible growth. As the plants perk up in late winter (February), gradually increase their food supply. Any houseplant fertilizer will do, but be sure to use it according to the manufacturer’s directions.
Some of these plants require special care, while others can’t be expected to “revive” once their blooms have fallen. The Christmas begonia, cyclamen, azalea, Christmas pepper and Jerusalem cherry should be discarded after the blossoms or fruit drop.
Remember that the fruit of the Jerusalem cherry is poisonous. Its miniature tomato-like fruit might look inviting to younger children, so be sure that your child knows they are not to eat.
Three plants that can be kept after the holidays are the Christmas cactus, the kalanchoe and the poinsettia. To keep your poinsettia for next season, place it in a dimly lighted room once the bracts or “petals” drop and water it only enough to keep its roots moist. Don’t be upset if all the leaves yellow and drop. The plant needs to go through a resting period.
In mid-April, prune the stems back to a 6 or 8 inch length, leaving only 2 or 3 nodes or joints per stem. Water the plant regularly and place it in a sunny window. When all danger of frost is past, repot your poinsettia in an organically rich soil in a clay pot and plant the pot in a sunny location in your garden. Make sure that the rim of the pot is buried or it will act as a wick, drying out the soil in the pot and the surrounding area. Mulch the area around the poinsettia and feed it lightly. Prune back any overly aggressive shoots.
In September, bring your plant inside. Beginning the 1st of October, give your poinsettia at least 14 hours of darkness a day for 40 days in a row by placing it in a closet from 5 p.m. until 8 a.m. Any interruption of this schedule will delay flowering. You should start to see color in the bracts by Thanksgiving.
Test the soil surface daily. When it feels dry to the touch, water it thoroughly enough to allow water to drain out of the bottom of the pot. If the pot is wrapped in foil, punch a hole in the bottom to allow drainage. With a little bit of work, you will be rewarded with a flowering poinsettia again at next year’s holiday season.
Happy gardening!