Introduction
Perennials offer an infinitely rich array of color, form, fragrance and texture. Perennials are plants that live for two or more years. Most provide seasonal color for one to three weeks. Many plant shapes and forms as well as leaf size, shape and color are available to add subtleties and character to a garden. There are perennials suitable for almost every area, however large or small and whatever the theme or style.
With thoughtful selection, perennials can be used to create borders with a prolonged season of interest. They can be used as a mixed border with shrubs, or with spring bulbs and long-flowering annuals to extend the flowering season. Designing perennials into a garden enriches a landscape. But equally important is the selection of adapted species and the type of care they receive. Consider the following basic cultural practices for perennials, then use the table to select adapted perennials for Southern Nevada gardens.
Soil Preparation
Compost should be added to the flowerbed every year. For a new bed incorporate 3 to 4 inches of compost, fertilizer and soil sulfur into the soil. Then cover the surface with a 3- to-4-inch layer of mulch. For every 100 square feet, spread 1/2 to 1 pound of fertilizer, such as ammonium phosphate (16-20-0), and 5 to 7 pounds of soil sulfur over the organic matter. Spade or rototill all these materials thoroughly into the soil 8 to 10 inches deep. Level and moisten. With the soil properly prepared it is time to plant. If the soil pH is unknown, a soil test from a nursery or lab is helpful.
Planting from Seed
Raising plants from seed is a simple and inexpensive means of growing a large number of plants. You will find directions on the back of the seed packet. You can sow in rows or broadcast the seed. After planting from seed, sprinkle a light layer of mulch over the area and firm the soil with the back of a rake. Soak the seed bed with a fine misting sprayer. Keep the seeds moist until they germinate, then water as needed. Small plants need special attention until they establish a root system in the bed. Remember, it may take a year or two before blooms appear.
Transplanting from Containers
Container-grown perennials may be planted at any time of the year. However, the heat of summer should be avoided. The best seasons for planting are fall and spring. Fall planting allows plants to establish quickly before the onset of cold weather. The soil is still warm; with moisture, roots grow well. To plant container-grown varieties, first water the plants well to ensure that the soil is moist. Allow to drain thoroughly. Next slide the plant out of the pot, taking care not to damage the roots or disturb the root ball. If the plant is root bound, straighten the roots and cut them back, if needed. Perennials should be planted with the crown at ground level. The top of the root ball should be planted level with the surrounding soil.
Perennials in Containers
The fastest way to establish a perennial garden is to buy nursery-grown plants. Plants grown in containers need more care than those in open ground, since they have limited supplies of nutrients and water. During the growing season keep the soil moist, but not waterlogged. In periods of hot, dry weather, plants will need daily watering. Lift and divide the plants when they become root bound about every two years, (depending on the variety) and plant in new soil-less media. If the container is to be reused, wash it well before replanting with 1 part household bleach or vinegar to 9 parts water.
Dividing Perennials
Perennials grow, and become crowded, producing fewer blooms and then begin to decline. This is the time to divide and rejuvenate the planting. Most plants should be divided during the dormant period—late fall or early spring. Division of freshly rooted perennials is best left until the end of their dormant season. In early spring, new buds will have begun to sprout, thus giving a good indication of the most vigorous and therefore most suitable material for planting.
Lift the plant to be divided gently with a fork, being careful not to damage the roots. Shake off any loose soil and remove dead leaves or stems to reveal the next season’s buds. Discard any old, diseased, dried out or damaged sections of the clump.
Watering
Newly planted perennials, even if they are low-water using natives, require moist soil. Any prolonged dry period will prevent roots from developing deeply and uniformly. Growth and performance can be permanently affected without proper soil moisture.
Apply water slowly in a basin around the plant’s root ball. Always water the areas thoroughly after planting. Sprinkling the soil, especially if it is windy, wastes water, increases evaporation, often causes crusting and does not ensure an even application. Regularly check the soil moisture around the root ball about 2 to 3 inches below the soil surfaces, especially the first few weeks.
The amount of water applied depends on soil type, exposure and the time of year. If planted on slopes, water in intervals. This helps prevent soil erosion. Do this by watering 5 to 10 minutes and allowing the water to soak in. Repeat in 1 to 2 hours with another watering until the moisture has soaked below the root zone. After plants adjust to planting and show growth, gradually space out the watering.
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