Garden Talk: September 1, 2005

From NGA Editors

Agastache 'Apache Sunset'

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Agastache or hyssop is an old-fashioned perennial plant that's gaining in popularity with the introduction of new varieties. Agastache is a versatile plant. It has attractive foliage and flower spikes that bloom in a range of colors, such as white, blue, pink, and red. The plant generally grows 18 to 36 inches tall, depending on the variety, likes full sun, and is hardy in USDA zones 5 to 9.

Agastache rupestris 'Apache Sunset' is a relatively new addition to the Agastache line. It features smoky gray, finely cut leaves on a 20-inch-tall plant. 'Apache Sunset' has salmon-orange flowers that emerge in midsummer and last until frost.

Like other Agastaches, it has aromatic foliage, too. The leaves have been described as smelling like licorice, mint, or even root beer when crushed. Whatever the fragrance, 'Apache Sunset' is a brightly colored, easy-to-grow, long-blooming perennial for your border that butterflies and hummingbirds will love as well.

For more information on Agastache 'Apache Sunset', go to: Bluestone Perennials.

Ultra Grow Container Liner

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One of the pitfalls of growing plants in containers is improper watering. Containers can dry out quickly or be overwatered by Mother Nature or overzealous gardeners. While underwatered containers result in wilted and stunted plants, overwatered plants can die quickly due to root rot from the lack of oxygen.

While most containers have drainage holes, another way to insure proper soil moisture and oxygen levels is to place an Ultra Grow Container Liner in the bottom of a container before you add soil and plants. The liner features a water reservoir that can release moisture up into the root system over time. The reservoir contains 20 "weep holes" that can be opened or shut depending on the water needs of the specific plants. The liner also has 40 drainage and aeration slits on the sides that allow oxygen to reach into the bottom of the container, while helping drain excess water away from the roots. The edge flanges are built to bend and adapt to a variety of container sizes and shapes.

The Ultra Grow Liner is made from UV-protected plastic and can last for years. For more information go to: Modern House Design Group.

Root Pruning Potbound Plants

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Fall is a great time to buy trees and shrubs at your local nursery. Most gardeners have heard that if your tree or shrub is potbound (roots encircling the rootball), you should score or break up those roots before planting.

Now research from the University of Minnesota indicates that this procedure may not be necessary. Researchers planted potbound linden and willow trees into test plots. Before planting, some of the trees' rootballs were scored (1-inch-deep cuts were made into the rootball), butterflied (rootball was cut in half), or teased (roots were hand pulled so they faced outward) to break up the circling roots. The control group was planted without any treatments. After two growing seasons the researchers dug up all the trees and recorded the numbers and sizes of the roots. Researchers found that none of the methods of breaking up the potbound roots prior to planting increased the size or number of roots, or the ability of the roots to grow into the native soil. They concluded that any roots encircling the plant above the root flare (base of the tree) should be removed since they may strangle the tree trunk as they grow. However, those below the root flare should be left as is, and they will naturally grow out into the native soil.

For more information on properly planting trees, go to: University of Minnesota.

Award-Winning Hydrangea

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Since 1978 the Gold Medal Plant Award Program at the Pennsylvania Horticultural Society has recognized trees, shrubs, and woody vines of outstanding merit. These winners are relatively new plants or varieties that are easy to grow, pest resistant, have multiple seasons of interest, and are hardy to at least USDA zones 5 to 7.

For 2006 a new variety of panicle hydrangea (Hydrangea paniculata) is highlighted. 'Limelight' grows 8 feet tall and 6 feet wide. It produces late-summer flower clusters that are smaller and more upright than other panicle hydrangeas. The flowers start chartreuse-green and turn white, pink, and finally burgundy in fall. 'Limelight' produces flower buds on new growth in late spring, so it should be pruned in early spring to control its height. It is best planted as a foundation shrub or in a border. 'Limelight' is hardy to USDA zone 4.

For more information on 'Limelight' go to: Pennsylvania Horticultural Society’s Gold Medal Plant Awards.

 
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