Home Hort Hints, April 2000

Rick Durham, Consumer Horticulture Extension Specialist, University of Kentucky
 
Seedless tomatoes

Did you know there are seedless, or parthenocarpic, varieties of tomatoes? Most were developed at Oregon State University. Many of these varieties are seedless only during the early part of the growing season, but become seedy as the season progresses. The fruit on these varieties also tends to be rough making them somewhat less desirable for fresh use. For this reason it may be hard to find sources for many of these varieties. I did find 'Gold Nugget' offered by Johnny's (<http://www.johnnyseeds.com>). You may have to do some looking if you want to give these a try. Here are some of the better varieties that have been released:

Don't cut those daffodils!

By all means enjoy the daffodils and other spring bulbs that are bursting into bloom. And be sure to cut some flowers for spring arrangements. However, leave the foliage alone until it starts to yellow which usually happens in late May or June. After the foliage has yellowed it can be cut to ground level. If the foliage is removed too early (for example, when the grass is mowed for the first time) there will be fewer blooms next year. If these is done year after year the bulbs will gradually lose vigor and decline. This is because the foliage is making sugar through photosynthesis, and sending this sugar down to the bulb for next year's show. This not only pertains to daffodils, but to other spring-flowering bulbs such as hyacinth, tulip, and crocus.
 

Pruning shrubs

Shrubs usually need pruning every few years. Depending on the type of pruning, the result may be to either thin out the growth or to make the plant more bushy. Proper pruning will also promote more flowering. The time of year for pruning depends on the flower habit of the plant. Spring flowering shrubs should be pruned just after flowering. Pruning later may result in a loss of flower buds for next years show. Summer blooming shrubs can be pruned in early spring since they produce flowers on the growth that occurs after pruning. Spring pruning will enhance the show of summer flowering shrubs.
    In some cases, shrubs become too woody and may exhibit decreased bloom. In this case, renewal pruning is practiced where 1/3 of the oldest stems are cut off low to the ground. The new growth will produce the desired blooms. The next year another 1/3 of the older stems are removed, with the remainder of the older stems removed the following year. These types of cuts tend to open up the shrub for better light penetration and air movement. If all the old stems were removed simultaneously, it would be difficult to control the vigor of the new growth. Such vigorous growth is susceptible to disease and inclement weather damage.
    For some shrubs, a more branching habit is desired. A pruning cut into recent year's growth, called heading back, will promote branching from buds near the cut. For shrubs where the canopy may be lopsided or have sparsely branched areas, heading back cuts may be the answer to promote branching and fill in the holes.
    Shearing is a pruning method often used on shrubs to provide a very formal appearance. Shearing removes only the tips of branches and promotes high foliage density at the end of the branch. This can be an unhealthy situation for the plant because sunlight and air do not penetrate into the plant's canopy. Shearing can also make plants, especially evergreens, more susceptible to spider mites and aphids. However, if shearing is practiced, make sure the top of the shrub is a little more narrow than the base of the shrub. This will allow the base of the shrub to receive some sun and reduce dieback of foliage near the base. Every few years, shear into older wood to invigorate the plant and ensure new branch formation. The shrub may temporarily lose some of its formal appearance but this will help to open the canopy and rejuvenate the plant. In all cases, be sure to collect the trimmings and dispose of or compost them. If left in the foliage, these dying branches may serve host to diseases and insects.
 

Plant your Easter lilies outdoors for flowers next year.

Since Easter is late this year, this will be an ideal time to plant Easter lilies in the garden after their flowers have withered. Remove the spent flowers and keep the soil moist until the plants can be planted outdoors. Wait until the threat of frost is past and select a well drained site in a sunny location of the garden. Good drainage is especially important for success with lilies. When planting, the bulb should be about six inches deep as measured from the base of the bulb to the top of the mulched soil surface. Since most bulbs are forced from the bottom of the pot, you should be okay to plant the lily at about the same depth as it was growing in the pot, assuming it was growing in a six inch or larger pot. It is important to work some of the garden soil in and around the root system to ensure that the plant will become well established. Water the plants in immediately after planting. Be sure to apply mulch to about two inches deep. Lilies like their "heads" in the sun and their "feet" in the shade. The mulch will help to lower summer soil temperatures. As leaves and stems turn brown they can be cut back to the first healthy leaf. New growth should emerge but it is unlikely the plants will bloom again during the first summer. Once growth has yellowed in the fall you can cut them back to the soil level and apply a generous layer of mulch once cool weather arrives. This extra mulch should be removed back to about two inches in spring as new shoots emerge. Remember that only potted lilies are programmed to flower at Easter. Your garden plants will flower naturally in June or July.
 

Things to do in April: