Perennials, Annuals, and Bulbs for April

While April is a month when springtime warmth begins in earnest, it's most beautiful certainty are two of the most beautiful shrubs in the perennial garden, forsythia and the oh so fragrant lilac. My grandfather used to say that when the lilacs bloom, it is time to sow seed that can take a nip (of frost that is).

  • When purchasing bedding annuals this spring, choose properly grown plants with good color. Buy plants with well-developed root systems that are vigorous, but not too large for their pots.
  • Do not select under-developed plants with shallow, poorly grown root systems that cannot absorb the moisture held in deeper soil and are more subject to damage from the rapid changes in temperature and moisture level typical of the soil surface.
  • Observe your daffodil and other spring bulbs while in bloom this spring to be sure they have not been shaded by the new growth of other tree or shrub plantings. If they have, you may need to move your bulbs to a new, sunny location or prune back the plantings.
  • Plants bought from greenhouses need to be hardened off before being planted in the landscape. Place newly purchased plants outside during the day, but bring in at night to protect from early season, cool, night temperatures that may injure or kill the plants. Gradually, the plants can be left outside for longer periods of time until they have fully acclimated and can be planted.
lilac in bloom

Lilac in bloom

  • In many zones (zones 7 and 8), try Saxifrages Saxifraga spp. for rock gardens, walls, and woods. 'Rock Garden Mixed' are easy-to-grow, mossy varieties that grow well on rock ledges and walls. The spring-flowering, soft, evergreen types S. umbrosa are more suited to rich, well-drained soil in cool and shaded spots, such as on the edges of woods.
  • Fertilize bulbs upon emergence of foliage with a 10-10-10 fertilizer, using a rate of 3 pounds per 100 square feet. Repeat the application after the bulbs have bloomed.
  • The cool weather of April is perfect for pansies. Brighten up your front door with pots of transplanted pansies or place them in outdoor beds as soon as the soil can be worked. Purchase large plants that will give a good show before hot weather arrives.
  • Lift, divide, and replant chrysanthemums as soon as new shoots appear. Each rooted shoot or clump will develop into a fine plant for late summer bloom. Pinch out the top when the plants are about 4 inches high to thicken the plant.
  • Mites, mealybugs, and root rot pathogens can be problems for dieffenbachia grown indoors. Control with insecticide soap spray. Spray this homemade aphid control mixture on the mites or mealybugs every few days until they recede. This home remedy to get rid of aphids, mites, and mealybugs will suffocate the aphids.
  • Try the new, semi-dwarf cosmos, 'Sonata White.' It is wind tolerant, grows to 20 inches high, and is great for cut flowers.
  • If growing vinca in a greenhouse, do not overwater, and keep the temperature about 80F. Vinca will wilt from too much water.
  • When growing houseplants in water, occasionally change the water completely (rather than just adding more) to keep mineral salts or algae from building up in the water.
  • Chickweed Stetlaria media is native to Europe, but has naturalized in all the temperate regions of the world. It roots easily along the stem and produces flowers and seeds from March through December. Chickweed can be controlled by hoeing early when the plants are still small. But bear in mind as you take it out that it is a most nutritious tea. You may want to find a spot to actually let it grow for this purpose.
  • If you want to plant an Easter lily outside, don't plant it near other lilies. Easter lilies may carry a virus that can infect other lilies.
  • Morning glories must be grown in a well-drained soil in a warm, sunny location. Rich soil and excessive fertilization yields vigorous vines with few flowers. Start seeds indoors in 4-inch pots for transplanting outdoors two or three weeks after the average last frost date. Soaking seeds in water overnight will speed germination.
  • As you plant asclepias, hostas, hardy begonias, and Japanese anemones, label them since they begin to sprout late.
  • Dusty miller, though usually treated as an annual, is a tender perennial. In warmer parts of the state, or if winter has been mild, plants may overwinter. If any come back in your garden this spring, dig and divide, replanting the more vigorous outside portions of the clump. Fertilize liberally.
  • Take chrysanthemum cuttings now through mid-June for flowers during fall and winter in the greenhouse.
  • To increase the apparent length of your flower borders when seen from inside, place the majority of the warm- and hot-colored perennial plants (yellows, oranges and reds) nearest the house. Concentrate the blues, which have a tendency to appear more distant, in the second half of the garden. Along with the blues, include some pink and mauve flowers. Plants with silver foliage can be used to provide a unifying ground color throughout. The actual dimensions of the borders and the paths separating them can help increase the illusion of distance. In a 20-foot-long border, make the planting about 1 and 1/2 feet narrower and the path about 1 foot narrower at the end away from the house.
  • Plan to attract hummingbirds to your garden this year by planting red or orange flowers. Monarda (beebalm) is a good perennial to provide nectar for these small birds.
  • When you are out shopping for annual flowers for your garden, look for plants with lots of unopened buds. Plants that bloom in the pack are often root bound and can be set back for several weeks after being transplanted. Plants not yet in bloom will actually bloom sooner, be better established and grow faster.
  • If you have a deck with a sturdy rail around it and would like a spectacular show this summer, attach a gutter along the outside of the top rail for a planter. Fill it half full of container- soil mix. Install one of the inexpensive, drip-irrigation systems that can be hooked directly to your garden hose to simplify watering and finish filling the gutter with soil mix. Plant your gutter planter with small, flowering plants appropriate to the available light. Impatiens are excellent in shady areas. Fibrous begonias are good in full sun or light shade. Petunias, ageratums and dwarf marigolds all perform well in full sun. Fertilize the gutter garden every two weeks using a water-soluble fertilizer according to package directions.
  • An unusual, hanging fern garden can be made with two wire baskets, some unmilled sphagnum moss, potting soil and small ferns. Line the baskets with the moss and fill the cavity with moist soil. Hold a piece of cardboard on top of the baskets and flip them over onto a workbench, then tuck small ferns securely over the surface of each basket. Again using the cardboard to keep the soil in place, invert one basket and place the other on top of it, forming a ball. Carefully slide the cardboard out, wire the baskets together, add a strong, wire hanger and hang the fern ball in a shady, protected place outdoors for the summer. Keep the fern ball moist.
  • Don't throw out the little gladiolus cormlets you dug out with the larger corms last fall. Plant them in a row in the garden this spring, and in two years, they will reach blooming size.
  • Plant dahlia tubers as soon as the danger of frost is passed. Stake at the time of planting to avoid injury to tubers.
  • To ensure the dahlia tubers you plant have survived storage, sprout them indoors in a warm, lit spot.
  • Consider planting flowers that can be dried for winter arrangements. Some of the best are strawflower, statice, Chinese lantern, celosia and globe amaranth.
  • To extend the blooming period of gladiolus, plant early, mid- and late-season selections each week until the middle of June. Choose a sunny location and plant the corms four to six inches deep and six to eight inches apart.
  • While commonly grown as a house plant, strawberry begonia Saxifraga stolonifera can also be grown as a ground cover in light shade. It is cold hardy to -10 degrees F.
  • Scatter annual poppy seeds in flower borders. The fine seeds need no covering. The plants grow rapidly and provide colorful flowers in early summer.
  • In a sunny location with poor soil, plant nasturtiums for a colorful show. They require warm soil to sprout and start blooming in about 50 days. Too much water and fertilizer produce excess leaves and few flowers.
  • Three levels of flowers add vertical dimension to patio planters. By grouping three flower heights (trailing, low edging and tall background) into one container, the maximum number of plants can be combined without crowding. For example, use trailing blue lobelias or ivy-leaved geraniums near the edge to form a cascade. Petunias or dusty miller can fill in the second story. In the background, use plants that will grow to 2 feet or more by the end of the summer and add height without heaviness such as large-type geraniums or Purple Ruffles basil.
  • When chrysanthemums show signs of life, dig up and divide large plants. Discard woody portions and replant divisions 12 to 15 inches apart.
  • Plant clematis in locations that receive at least six hours of sunshine a day. Use an organic mulch or ground cover to shade roots and keep them cool. Plant in rich, well-drained loam.
  • Aster contraster is the world's first aster with stripes. The fully double, incurving, three-inch blooms come in a wide range of color. Pinks, carmines, blues, lilacs, rose and mauve are contrasted with a white stripe. The plant is dwarf, reaching only 9 to 12 inches, with a round compact habit. A. contraster looks equally well in a tub on the patio or planted as a group in the garden.
  • The Connecticut Agricultural Experiment Station reports that larger plants with more flowers can be grown in a soil mix consisting of 1 part sphagnum moss, 1 part peat moss, 2 parts perlite and 2 parts compost than with 4 other commonly used mixes. Sphagnum moss is reported to increase aeration and water-holding capacity and to suppress soil-borne diseases.
  • Many popular perennials can be divided now including: phlox, fall asters, shasta daisies, baby's breath and liriope. Set up a plant exchange with friends and neighbors to share the excess.
  • Planted now, Sedum spectabile and Hosta tardifolia or H. plantaginea will brighten your flower bed in the fall with flowers. Aster novae-angliae, which is a blue aster, or the red chrysanthemum cultivar 'Minn Ruby' are also late blooming.
  • When iris leaves appear thin and limp, check for borers. These grub-like insects can ruin an entire planting if not detected and eradicated early.
  • Fill the bare spots in the flower bed with moss roses Portulaca and feed regularly to encourage blooms into the summer.
  • Blue amaryllis Hippeastrum procerum and green amaryllis H. calyptrata present a rewarding challenge to patient gardeners. Seeds, available from select, mail-order, seed companies, bloom in about five years.
  • For hot-weather color, select one of the following: Gloriosa Daisy, Madagascar Periwinkle, Ornamental Peppers, Mexican Zinnia or Amaranthus 'Joseph's Coat.' Plant after all danger of frost is past and plan for color until winter arrives.
  • April is a good time to clean up plants and flower beds. Pick out dead leaves and twigs and prune dead limbs.
  • Make a plot layout of your flower borders. This is a very essential, but easily neglected, chore. With an accurate plot plan, you will know where to locate the spring flowering bulbs you plant next fall. Also, it will make your spring and summer gardening easier. You will be able to correctly identify the plants in your border and plan for continuous blooming by setting young annuals between bulbs and early flowering perennials after their blooms have faded.
  • Label the clumps of daffodils that are too crowded, as overcrowding inhibits blooming. Dig up and separate in July.
  • Cut flower stalks back to the ground on daffodils, hyacinths and other spring flowering bulbs as the flowers fade. Do not cut the foliage until it dies naturally. The leaves are necessary to produce strong bulbs capable of reflowering.
Gardening is an exercise in optimism.
Sometimes, it is a triumph of hope over experience.
- Marina Schinz   ... more gardening quotes

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