Tidewater Gardening - April 2013

Spring Flowers and Showers


K. Marc Teffeau

Yea! Spring has arrived! I have to admit, however, that this past winter really was not bad. We only had a few really cold days in January. And we also received a decent amount of rain to help with the spring green-up.
The only plants that I think suffered from the winter were the fall planting of pansies. Most of those plants were turned into green and multi-colored piles of mush in the landscape. But do not despair! There are spring transplants of pansies in the garden centers, so go out and replace them to provide some great color in the landscape until the weather really gets warm in June.
The mild winter has a lot of our spring flowering plants jumping early ~ especially the spring flowering bulbs. Be sure to cut the flower stalks back to the ground on daffodils, hyacinths, and other spring flowering bulbs as the flowers fade. Do not, however, cut the foliage back until it dies naturally. The leaves are necessary to produce strong bulbs capable of re-flowering.
Flowering bulbs do have nutritional needs, as many species feed quite heavily. It is important to remember that a plant that grows from a bulb can only take in nutrients while its leaves are green and the plant is growing.
To keep the planting going, you can fertilize bulbs upon emergence of foliage with a balanced fertilizer like 10-10-10, its organic equivalent, or a liquid fertilizer. There are also fertilizer mixes on the market that are specially formulated for use with bulbs. The important thing is, no matter what formulation or type of fertilizer you use, fertilize the bulbs in the spring before the foliage dies.
Late April is a good time to plant dahlia tubers in the flower bed. If you dug up and stored dahlia tubers over this winter, one easy way to determine if they have survived storage is to sprout them indoors in a warm, well lit spot.
If you have bare spots in your flower bed, why not consider moss rose portulaca. This annual’s flowers range from bright reds, oranges, yellows and purples to pinks. Moss rose grows 4 to 8 inches tall and spreads up to 2 feet, making it a great groundcover.
Many of us like to feed the birds in the winter. Have you ever looked under the bird feeder in the spring? From the bird seed that has fallen on the ground, the area under and around the bird feeder experiences an explosion of little weeds in the spring. Thistles, sunflowers, millet, corn and other grains are starting to germinate from the spilled wild bird seed. The grass-like small grains will succumb to regular mowing. In flower beds or vegetable gardens, lightly scrape the seedlings off with a hoe, then replace the disturbed mulch. You may need to periodically pull or hoe additional seedlings over the next several weeks after the first ones appear.
There is plenty to do in the perennial flower bed in April. Hardy chrysanthemums are one of those perennials that need to be divided in the spring. They have a tendency to spread by underground stems. This multiplication of plants increases the demand for water, light and nutrients. Over time, crowded mums will result in smaller flowers. If you want your chrysanthemums to produce the large flowers they once did, it is important that you divide them now.
To divide the mums, simply dig up each clump as soon as you begin seeing new young plants growing near the base of the old stems. Shake as much soil from the roots as possible to facilitate dividing. Next pull apart small clusters of young plants from the large clump. Small groups of plants are much simpler to divide than an entire clump.
Next, separate these small clusters into individual plants or into groups of two to three plants each. Make certain that each plant or group of plants have adequate roots for transplanting. Replant them in the bed or move them to new locations in the yard.
Pinch out the top when the plants are about 4 inches high to thicken the plant. You can also take chrysanthemum cuttings now through mid-June for flowers during fall and winter in the greenhouse.
If you have an herbaceous perennial bed or garden, it will benefit now from a good feeding and a liberal fertilizing. Perennial gardens can most easily be cleaned by raking with a good steel lawn rake. Old plant tops that are not removed in raking should be cut with a sharp pair of grass clippers. If you mulched your perennial bed last fall, as you should have, avoid raking and simply clean each plant by hand so as not to disturb the mulch.
After you have cleaned your garden, examine it carefully to make certain that each plant will have sufficient room to grow. If your plants appear to be crowded, now is the time to divide them and probably give a few to your friends and neighbors. Spring is also a good time to increase the variety of perennials in your garden.
Late April is also vegetable growing time. The last planting of cool season crops such as carrots, lettuce, spinach, potatoes, and turnips can be done. If you want to have a vegetable garden, but have limited space, like an in-town lot, here are some ideas to maximize your garden plot.
First ~ keep walkways to a minimum. Paths between every row often aren’t necessary. Plant in beds rather than in individual rows.
Second ~ intercrop your plantings. Mix slow growing and fast growing vegetables in the same row so that the “speedy” vegetables have matured and been harvested before the slow one needs the space. Inter-planting carrots and radishes are a good example.
Third ~ stagger plantings. Alternating plants between rows allows more plants in a given area than evenly spaced rows.
Fourth ~ raise vine-type crops vertically. Grow cucumbers, tomatoes and pole beans on fences, trellises or stakes to save space.
Fifth ~ sequence your plantings in the garden. As soon as a row of vegetables is used, cultivate the ground and replant with another crop which will mature before the frost. Replace early cool-season vegetables with warm-weather ones as the first mature and are harvested. In mid-August, start cool-season crops again for fall harvest.
Sixth ~ garden in containers. If space is very limited you can grow some vegetables such as eggplant, pepper, and tomatoes on the patio in containers. There are now even compact varieties of cucumbers that can be grown in small spaces. Check the descriptions in the garden seed catalogs or on the back of the seed packet to see how much space they require.
Finally ~ use your flower beds to grow vegetables. There is no rule that says you can’t grow vegetables in a flower border. Some can make an attractive addition.
In selecting a site for vegetables, make sure that they will get sunlight. Most plants require six hours of full sun per day. When planning the garden, remember to avoid locations near buildings and fences that cast long shadows. Particularly stay away from trees and shrubs which not only cast shade but also remove moisture and nutrients for the soil.
If you are in doubt about the amount of light the spot will get, grow lettuce, parsley or some other leafy vegetable there that can get by with a little less sun.
Give your transplants a “jump start” with a starter solution when planting. Use a water soluble fertilizer at half the label rate in a gallon of water. Pour a cupful of the solution around the base of each young seedling or transplant, being careful not to splash the leaves which could cause injury. The solution promotes root growth and gives the plants the extra energy needed for quick establishment.
In the landscape shrub bed, now is the time to be fertilizing and mulching your azaleas. They will benefit from an early spring application of one pound of ammonium sulfate fertilizer per 100 square feet of bed, if you have been fertilizing regularly. Apply 2 to 3 pounds of 5-10-5 fertilizer per 1000 square feet if your plants have not been fertilized for the past couple of years.
Sprinkle the fertilizer on the surface of the soil around the plants and water in. It is always a good idea to have the soil in azalea and rhododendron beds tested every couple of years to make sure that the soil pH is 5.5. or below.
To maintain proper soil moisture and prevent the weeds from growing, mulch the plants with 2 inches of pine bark, pine needles or shredded hardwood mulch. If adequate mulch is already present, do not add additional inches! Over-mulching is the quickest way to kill shallow rooted plants like azaleas. If you have a mulch layer higher than 2 inches, this can result in the production of a secondary root system in the mulch at the expense of the primary root system.
When the mulch dries out, the roots will die and the plant will also. Many times all you need to do is a gentle “fluff up” the existing mulch to make the plants look nice.
Happy gardening!

Marc Teffeau is the Director of Research and Regulatory Affairs at the American Nursery and Landscape Association in Washington, D.C. He lives in Preston with his wife, Linda.