• First of all–patience! April is early in our gardening year. As soon as we get a taste of the warm weather to come, we gardeners get itchy to garden! Remember that the “early risers” are first to wake. Don’t assume that plant you bought last summer didn’t survive because it’s not rising with the bleeding hearts. Many plants won’t break dormancy until the end of April, early May. Don’t make rash decisions.
• Perennials can be divided and transplanted when new leaf growth is 3 — 4 inches high including Japanese anemone, yarrow, hosta, astilbe, phlox, asters, black-eye Susan, chrysanthemums, and daylilies. Use the double-fork method to split the crown.
• Trim back the leaves of liriope and mondo grass before new growth starts
• Mulching – organic mulches do break down and need to be “top dressed” every year or two. When adding mulch over top of existing mulch, make sure the total depth does not accumulate more than 3 to 4 inches as too mulch is detrimental to your plants.
• Maplewood = many shady yards. You can create wonderful shade gardens with hellebore, trillium, bleeding hearts, violets, primrose, shooting stars, lily-of-the-valley, pulmonaria, ferns, and bulbs (muscari, daffodils, and bluebells).
• Spread slow-release fertilizer around ornamental plantings – trees, shrubs, and perennial beds.
• Repot wintered-over container plants with fresh soil, larger pot and slow-release fertilizer
• Roses – there are many approaches to fertilizing roses. If you want flowers this is the one plant you will need to feed. Mid-April is the time for the first application.
• An enormous group of perennials can be started now from seed. Several include asclepias (milkweed), baptisia, (false indigo), callirrhoe (poppy mallow), hepatica, hosta, and hyssopus (hyssop) and solidago (goldenrod). For germination needs, check the seed-packet instructions, propagation guides or the Thompson & Morgan website (www.tmseeds.com) for a similar seed in the same genus.
• Fertilizing – incorporate 5-10-5 or 10-6-4 fifty percent (50%) slow release fertilizer into the soil during soil preparation for transplants and new plantings. Do not simply toss a handful of the fertilizer into the planting hole because it will burn the roots.
• If a late hard frost is expected after flower buds on some shrubs have started to swell (e.g. camellia), cover with a sheet, drop-cloth or newspaper.
• Prune out dead or winter-damaged branches on shrubs. April is a good time to prune:
Buddleja davidii (butterfly bush) (but NOT Buddleja alternifolia (“alternate leaf butterfly bush)
Caryopteris (blue beard, blue mist)
Nipponanthemum nipponicum (Montauk daisy)
• Rake and aerate the lawn …
• Crab grass control – it is important to remember that herbicides for crabgrass control work by preventing seed from germinating. Therefore, it needs to be applied before seeds germinate. A good rule of thumb is to apply half the recommended pre-emergent crabgrass control when the forsythias and Bradford pear trees bloom. Apply the other half 6 to 8 weeks later.
• Set out transplants for cool season crops such as cabbage, broccoli, cauliflower, edible-pod peas, spinach, kale and onions. Make sure they are “hardened-off” before planting in the garden in mid to late month.
• Lettuce and other salad greens can be planted, but you will want to have a row cover fabric ready should a cold night be forecast.
• It takes about 6 weeks to grow transplants for tomatoes, peppers and eggplants. The first week in April gives you about the right amount of time to plant seeds to be ready to plant out in the middle of May.
• Water newly planted transplants and seeds that have been set out. Make sure transplants are moist before they go in the ground. If it does not rain, water seed daily until they germinate. Seedlings indoors are still best watered from the bottom.