APRIL HORTICULTURAL HINTS
Tread softly. The soil around your home and garden is just coming out of its winter hibernation of alternate freezing and thawing. Right now, the top few inches of soil is exceptionally airy, and every time you walk over it, you compress some of the air out. By the end of April, the soil should be ready for gardening but, for right now, avoid doing damage to your soil by walking on it too much.
Spray dormant oil now to control aphids and other insects on your trees and shrubs. Commercial dormant oil sprays have an emulsifier added to allow the oil to mix with water. Spraying trees and shrubs now, before buds break and leaves appear, will kill eggs and insects while not affecting foliage or harming birds or mammals.
Check before you sow early vegetables. The best test of soil readiness for a home gardener is to take a small handful of soil and squeeze. If it holds together as a wet clump, or heavens forbid, water squeezes out, you need to wait and hope for sunny dry days. Seeds put into cold wet soil will rot. Further, working cold, wet soil with a tiller or spade will destroy the soil structure. When it is ready, plant peas, turnips, spinach, cabbage, lettuce and other cool weather drops.
In the flower garden. Any remaining perennial tops from last year should be cut off and removed before new growth begins. A thin top dressing of compost around perennials prior to this year’s bloom will enrich the soil.
Resist the temptation to apply mulch now. Applied too early (and April is too early in Massachusetts), the mulch will slow down your garden by acting as a blanket, preventing warming and keeping the soil colder than the air. Later on, those 2 to 3 inches of mulch will keep down weeds and dress your garden.
Strawberries. Start your strawberry bed as soon as the soil can be worked. For new plants, start a new raised bed by creating one at least eight inches deep using a mixture of good soil and aged manure or compost. Because strawberries prefer to grow in a somewhat acidic environment, test the soil for pH and, if it is greater than 6, amend the soil as needed. Create a small mound of soil in the center of a hole. Fan the roots over the mound so they are spread throughout the hole. Be certain the crown of the strawberry is placed so that it is half under the level of the bed and half above when the soil has been firmed in place. This way it will not be likely to rot or be smothered. Water thoroughly and mulch. Heat treated straw or pine needles make an excellent weed free mulch that will also keep the developing berries clean.
What, and what not, to prune. Everyone likes to prune in April, but follow these guidelines: Prune spring blooming trees and shrubs only after the flowers are finished. Don’t be in a hurry to prune off brown areas on evergreens. They often will regrow the needles that have suffered winter kill. A light scratch with your fingernail on the branch will show green if the wood there is still alive. If you have fall-flowering shrubs, this is your last call to prune them.
Seasonal forecast. The Drought Monitor issued at the beginning of April shows some danger for New England. Portions of the region are ‘unusually dry’ and Vermont and a small area of New Hampshire is in Stage 1 drought. No area rates ‘severe’ or ‘extreme’. But the same map at the beginning of March showed no drought at all in southern New England. The NOAA’s Climate Prediction Center shows a 50% probability for higher-than-average rainfall for April to June for New England; it also shows a 60% probability of above-average temperatures. Keep these forecasts in mind (and watch for updated ones) as you go through the season.
Garlic mustard is a very invasive weed that easily out-competes native plants. In early April, garlic mustard pulls easily – roots and all – out of the ground. Be sure to wear gloves because the sap from the plant can cause a painful, poison-ivy-type rash. Once garlic mustard flowers, each plant can produce thousands of seeds that remain viable in the soil for years.