Getting Your Garden ready for spring
The end of February is the best time to start preparations for the new season. The risk of severe frost is low, and a few days are pleasant enough to tempt us out into the garden. Pruning should be the first priority – to remove dead material, open up the structure of the plants, direct their shape, and stimulate new growth. Fertilizing is important at this stage, when plants are putting on new growth and beginning to set their flower buds. Mulching is the final step to get your garden off to a good start for the season.
The first job is to cut to the ground any remaining foliage on herbaceous perennials (i.e. those that die down each year.) Herbaceous grasses can also be cut back now, before there is any danger of cutting off the tips of the new blades.
Evergreen and semi-evergreen perennials such as Penstemons can now be cut back to just above the new growth that is starting near the base, to give bushy, compact plants. Woody sub-shrubs such as Lavender, Santolina, and some Artemisias should also be cut back hard (but not into bare wood) to stimulate growth from near the base.
The aim in pruning woody deciduous shrubs is first to remove any dead or diseased material, then to remove branches rubbing on other branches, crossing over the center of the plant, or spoiling the shape of the plant. Generally no more than about a third of the branches should be removed, and where possible, these should be the oldest branches. Finally, the remaining branches can be cut back to just above a healthy bud to direct the shape of the plant. Modern roses are usually pruned back to a point where only a few buds remain. Shrub roses do not need such heavy pruning. In both cases, pruning cuts should be made just above an outward-facing bud to open up the structure. Hydrangeas (which should have the dead flower heads left on during winter to protect the new buds) can be cut just above the first pair of healthy buds that you find below the old flower head.
Evergreen shrubs need less pruning—usually just to maintain a good shape. Early-flowering shrubs, such as Camellias and Rhododendrons should not be pruned until after they have flowered. Summer-flowering Clematis should be cut back now to about 12 inches from the ground if they weren’t cut back in fall. Other deciduous flowering vines, such as Wisteria and Honeysuckle should be cut back to leave just a few good buds on each branch.
After cutting back, plants go through a period of rapid growth so it is important to give them a source of nitrogen. Phosphorus is needed to promote flowering and root growth, and potassium is also important for general plant health.
The easiest way to provide these and other nutrients is by using a slow release solid organic fertilizer such as Dr. Earth® All Purpose Fertilizer (4-4-4) or, for roses and clematis and other long-flowering plants, Dr. Earth® Rose and Flower Fertilizer (5-7-2). These products also contain soil microbes and micorrhizae to help the roots absorb nutrients. The granules are simply scattered around the plants and lightly worked into the soil. There is usually enough rain this time of year so that watering the fertilizer in is not necessary.
Mulching is important because it reduces water loss from the soil, stabilizes the soil temperature, smothers annual weeds and reduces the germination of weed seeds. Another benefit is the effect on the appearance of the garden. After the moving, dividing, and planting of fall and spring the soil surface is usually uneven, with rocks and different types of soils exposed. Mulch covers all this, and makes it look as though you really know what you are doing!
There are lots of different types of mulch, and every gardener has his or her favorite. Some are inorganic and so do not add any nutrients to the soil. Examples are gravel and various landscape fabrics. Some are organic but decompose so slowly that they do not provide nutrients, and may actually use nitrogen from the soil as micro-organisms break them down. Examples are coarse bark and other wood products. Compost is a good organic mulch—it is not very high in nutrients, but it does rot down and improve the soil texture. You can make your own compost, or use bagged products like Gardner & Bloome® Soil Building Conditioner, which contains mycorrhizae. Various manures are higher in nutrients and are good mulches if well composted so they do not scorch the plants. There are several products composed of manure mixed with sawdust or other wood product. Examples are bagged Gardner & Bloome® Farmyard Blend and bulk products with names like Fertil-Mulch or Comp-Mulch. These are lighter and easier to apply than straight manure but also supply nutrients as they break down or are worked in.
Whichever mulch is used, it is important not to apply it right up to the crown or stem of the plant as this can cause rot. In practice, in a closely-planted garden, this means you can only apply a couple of inches of mulch. In a well-spaced shrub or tree planting up to four inches can be used.