Perennials are plants that return year after year. Each fall their stems and leaves die back to the ground while their roots remain alive, but dormant, beneath the soil. There are thousands of perennial plants, but a few of the plants we use most often are: daylily, hosta, astilbe, daisy, coreopsis, blue salvia, and rudbekia. It is important to understand that perennials spend their first one or two growing seasons establishing strong root systems. Because of this, the foliage and flowers may not be extremely showy for the first few years. Be patient with perennials—they are well worth the wait!
The following guidelines are true for perennials in general:
- Slightly moist, well-drained soil high in organic matter.
- Apply a 2-3 inch layer of mulch(such as pine bark mulch, pecan hulls, or compost) around plants at least every other year to help keep weeds down, retain soil moisture, and keep soil cool.
Perennials do not have the extensive root system of a tree or shrub, so they will need to be watered more frequently. Most of these plants will wilt quite quickly if not given enough water. It is especially important to water them well in their first season of growth. They may need to be hand-watered if a sprinkler does not effectively cover them.
- Water deeply at least once/day when temperatures are very high in the summer.
- Water deeply 3 times/week in the spring and fall.
- Always water any plants either before 9AM or after 8PM, especially in the summer. If you water in the heat of the day, most of the water will actually be lost to evaporation. Also, water droplets left on leaves in the scorching sun can cause unsightly discoloration, burning, and withering of leaves.
The best way to feed perennials is by keeping the soil rich in organic matter. This is done by regularly adding compost or soil conditioner to your garden soil. A balanced fertilizer can be applied in spring or early summer. Fertilizing in late summer or fall could make new growth vulnerable to frost damage.
The best way to propagate almost all perennials is by division. In either spring or fall, the whole plant is dug out of the ground and literally divided into several plants by the roots. This can be done on average every 4-5 years.
Deadheading is simply removing spent flowers from the plant. It is usually easiest to do by hand, but scissors or pruners can be used as well. It is beneficial practice for almost all flowering plants. Removing the dead flowers promotes growth and stimulates new flower production, removes a potential target for diseases and insects, and keeps the plant looking nice and neat.
Pest and disease problems vary widely by species. In general, if you notice holes in leaves, yellowing or discoloration of leaves, wilting, white fuzzy growth on stems, leaves, or flowers, or any other sign that the plant looks unhealthy, check with a local extension agent or garden center for possible treatments.
Plant Care Guidelines