Trees & Shrubs
Receiving an appropriate level of moisture is the most important factor in establishing newly installed plant material. Plants are equally sensitive to both over watering and under watering. Suitable watering of plants includes maintaining the correct amount of moisture and using the proper method of application. For the first two to three weeks after installation, plants should be soaked two to three times per week. After three weeks, plants should receive approximately one inch of water per week in one application, or more when temperatures exceed 85 degrees Fahrenheit. Plants benefit most from a thorough soaking at the soil line rather than sprinkling the leaves or the mulch bed. Recommended watering times are in the early morning or in the late evening hours. Be careful not to over water. More plants die from sitting in standing water than from not receiving enough moisture.
Most plant materials benefit from the periodic application of fertilizer nutrients during the growing season. A granular type of fertilizer, such as 12-12-12, may be applied to the soil line of trees and shrubs each spring. Acid loving plants such as azaleas, rhododendrons, and yews will green up with soil application of granular aluminum sulfate each spring and fall.
To enhance the blooming and flowering of your shrubs you can apply a foliar spray of a general fertilizer (Peters, Miracle-Gro, or Miracid) every two to three weeks. When applying fertilizer, cover the leaves of the plant and spray the fertilizer at the soil line. For every fertilizer always read the manufacturers label for the best timing of the first application, over application can burn the plant material.
To keep your established plants looking full and attractive, prune away dead branches and remove spent flower heads. This will encourage new growth and compactness. Most trees and shrubs should be pruned in the spring or fall after they have finished flowering. Remember to make all pruning cuts immediately above a growth bud on the branch and not in the middle of the stem. Shearing is not recommended if you want to keep the natural form of the plant.
For plants that bloom before June, all pruning should be done after the bloom cycle in the spring or early summer. Shrubs with pithy stems (i.e. Butterfly Bush, Caryopsis, and Hydrangea) should only be pruned in the spring.
Perennials are among the most useful plants for home landscape. They are colorful, diverse, and can be used as more or less permanent features. While trees and shrubs provide the outline shape and sometimes the backdrop of the landscape, non-woody perennials can provide more detail and accents. Herbaceous plants grow best in well cultivated, fertile, and moist but well drained soil. Most perennials should be planted in soil that does not remain wet throughout the winter, and doesn’t become too dry in the summer.
Preparation of Soil
Soil preparation of perennials is best begun ahead of planting time. An early start helps eliminate the unwanted grass, and broad leaf weeds can be eradicated. Large clumps can be removed by hand during digging, or they can be tilled under (perennial grasses should be removed and destroyed or composted). Fresh weed seedlings often from seed brought to the surface during soil preparation are easily killed by hoeing or cultivation in the days and weeks after the soil has been prepared.
Incorporating organic matter, such as well-rotted manure, peat moss, compost, or leaf mold, improves clay soils by increasing the soil pore space and thus increasing aeration and drainage capabilities. In quick draining soil, the addition of organic matter is also recommended to increase the soil’s ability to retain water and nutrients.
Place the individual plants out in their containers, on or near their planting positions. Dig holes big enough for the root systems. Handle the plants one at a time so the roots have the least exposure to dry air. Hold each plant in its hole and tumble loose soil around roots and other underground parts. Gently firm the soil around smaller perennials. Larger plants should be firmed in more securely. Water each newly planted perennial so soil and roots settle in together. In dry conditions plants are best planted with plenty of water so that surrounding soil is moist.
Gardening with perennials and annual plants should be pleasurable and rewarding. To maintain herbaceous plants and prepare them for the changes in seasons, you will need to: water, stake, deadhead, pinch, fertilize, mulch, hoe, and divide them.
Watering & Fertilizing
Watering is necessary whenever something new is planted, when the soil is dry, or when you receive plants from a nursery or garden center and must leave them in their containers until they are ready to plant. The one important rule for watering is to give the plants a thorough soaking at the roots. The need to water perennials varies from place to place, as well as month to month. Fertilization for perennials is usually needed once or twice during the growing season. Make one early summer application of a granular 5-10-5 formulation at a light application rate (2 pounds per 100 square feet, or one or two liquid fertilizer applications at half the recommended rate to avoid burning tender young shoots and overdosing with nitrogen which leads to excessive leafy growth).
For established perennial plantings, surface or liquid applications, or even an all around garden fertilizer, two to three times during the year will provide adequate amounts of plant food. One application should be in early spring while plants are still dormant, another six weeks into the growing season, and the third application is mid to late summer.
Foliar sprays of dilute liquid fertilizer will bring almost immediate, though short-term results. For the best results when plants show signs of nutrient deficiencies combine foliar feeding with soil applications. A regular fertilization program should ensure healthy plant growth and development.
When perennials are small it is easy to hand weed. You can also hoe lightly between the plants to prevent weeds from becoming established and from competing with the perennials for moisture and nutrients. As perennials grow and spread, weeds will be fewer. Remove those that do grow so the perennials can continue their unrestricted development. To help with weed control and moisture conservation, apply a layer of shredded bark mulch between the plants.
Mulching with bark, peat moss, or other organic material will improve the air/water relationship in the soil. Most perennials perform better with an application of mulch in the fall. This will protect against winter damage.
Taller growing perennials may need support to prevent their drooping. While the plants are still fairly short and before they start to fall, insert a support structure. Subsequent growth will cover the structure.
Pest & Disease
Herbaceous perennials are susceptible to damage from insects, fungal, bacterial, and viral diseases. The key to managing pests and diseases is to provide your plants with the best possible growing conditions.
Most herbaceous plants are easily divided during the dormant season. Lift them from the soil and break them apart into several pieces, either by inserting two garden forks into the clump back to back and levering it apart, or by gently separating the roots with hands or a trowel. Discard older central portions and plant the outer newer parts.
Plants with fleshy roots, such as daylilies, can be divided by digging the plant out of the ground and cutting the roots with a knife. Be sure each piece has two to six buds showing signs of upward growth before replanting. For most herbaceous perennials early spring and early autumn are the best times for division.
Fall is the best time to lift and divide spring and summer perennials, in all but the coldest climates. Otherwise, divide perennials in the spring.
Fall Cleanup & Preparation For Winter
When top growth has died back, trim for neatness as desired. Clean out weeds before they become established. Dead top growth may either be removed (this is necessary if it is likely to harbor fungus and insects) or left as a protective mulch for the underground parts during winter. If it is trimmed back to within a few inches above ground, apply winter mulch after the ground has frozen (this will protect against alternate thawing and freezing which tends to lift plants out of the soil). Remove any remaining tops and the winter mulch in very early spring.