Lesson 5: Annuals, Perennials and Biennials
What Are Perennials?
Perennials are one of your garden’s foundation plants. In ideal conditions this class of plants can live and bloom many years. They can be divided into new plants after they’ve reached their full growth in 2-3 years. This makes them a sensible, economic choice for basic plantings.
The variety is stunning, and includes daisies, chrysanthemums, foxgloves, pinks, ajuga, geranium and many, many more. If you don’t mind a slow start, buy the perennials you select in 1 gallon containers. This will give them plenty of time to throw down a healthy root system and establish themselves. You can find them in 5 gallon containers, but these will be much more difficult for the beginning gardener to establish.
In order to select the right plants for your particular microclimate, drive around your neighborhood and see what appears to be growing well. Contact your local Master Gardener, who can advise you on the best choices, or tell you if what you are thinking of planting will grow well for you. In addition, reading up on this class of plants and doing online research should give you enough information to make good choices.
When you are ready to plant in your prepared beds, slip the plant out of the container. If there are heavy roots wrapped around the soil, try and untangle as many of them as you can. If there are too many or this is too difficult, take a very sharp knife and make an X cut through the roots on each side of the soil mass. This will stimulate new root growth. Set the plant in the soil, fill and gently tamp down all around to eliminate air pockets. Create a small basin around each plant and water in well. You can then apply mulch to keep the roots cool and hold down weeds.
Dividing perennials is easy. Take a very sharp shovel and slice down the middle of the mature plant. For very large plants you will need to lift one section out and divide it in half again. Place the sections in their new planting beds, and replace the soil around the “mother” plant. Using rooting or transplant hormone is a good idea to help minimize shock.
If you have chosen wisely and keep them fed and watered, they will reward you for years to come.
Woody Perennials
Peonies, hibiscus, hydrangea, camellias, and azaleas are part of this wonderful class of perennials. Woody perennials can be used as specimen plants or used as shrubs in most any garden. Fussier than the other plants we’ve discussed, they are still worth their weight in gold, for sheer visual impact.
Many of the above varieties like a slightly sour soil. And can benefit by regular feedings with an acidifier or specially formulated food. Some only bloom in one glorious flush in the Spring: azaleas, camellias and peonies are good examples. Feeding for early bloomers can begin as early as January.
Some woody perennials will need pruning to keep them in shape others only need a light touch up. Always use a very sharp pruner and an angled cut.
Good air circulation is extremely important as is keeping spent blooms and foliage picked up. Camellias get chlorosis quite easily, so a feeding of iron once a year is recommended. Hydrangeas will pink up in alkaline soils. So to get the desired blue coloration, adding sulfur to the soil will help bring the pH up. If you notice a mushy browning on the edges of peony or camellia petals, they are getting too much water. Water only at the base of the plants, and avoid overwetting of any foliage.
In the Fall, spraying the woody stems and branches with dormant oil, and again in the Spring before buds appear, will help smother any soft bodied insects, trying to winter over in your plants. Because many of this class are prone to mildew and blackspot, treating with horticultural copper is advised.
Keep the soil turned and refreshed with compost and a small amount of sulfur. This will help keep them healthy all through the Spring.
Herbaceous Perennials
Herbaceous perennials are excellent choices for drought-ridden areas of the country. Requiring little in the way of extra feeding or water, they will thrive happily for years. The most important thing is planting them properly in good soil to begin with.
Many gardeners grow herbaceous plants to add color and texture to the spring, summer, and fall landscape. "Herbaceous" means non-woody, and includes many common annuals and perennials grown for bloom or foliage effect. Success is nearly assured if a proper planting site is selected and good cultural practices are followed.
Artemesia is a wonderful example of this class of plant. With its silvery grey foliage and feathery texture, it makes a stunning contrast to darker green plants. Lambs ears have a pleasing velvety texture and low mounding habit, making them ideal for border gardens.
Scented geraniums, originally imported from Africa to the Netherlands and brought here by the Dutch, are versatile and highly aromatic. These are very different from the common pelargoniums, or garden geraniums. The scents are heavenly. Rose, lime, nutmeg, lemon, vanilla and orange to name a few. The leaves are "toothier" and not rounded like the others and the stems can get woody at times.
All herbaceous varieties require little disease or pest control. Weeds can be kept under control by mulching, which helps conserve water. If you want to feed them, use a mild, low nitrogen fertilizer to give them a boost every so often.
Take some time to learn all about these interesting and versatile plants.
