Caring for Your Perennials
Improving Your Success with Perennials
There are a number of factors to consider and procedures to follow that will enhance the success and performance of your new perennial. We have compiled some brief summaries of areas that will improve the production and longevity of your new plants below.
Upon receiving your new plants, it is important to open the shipping box(es) immediately. Carefully remove all packing materials and containerized plants from the carton(s). Do NOT keep the plants in the shipping boxes as this will reduce plant quality and may lead to plant disease or death. If the potting mix is dry upon arrival, apply water to the containers until the root zone is thoroughly moist. When possible, plant your new perennials within 1-3 days after they have been received. If it is not possible to plant them within this time period, keep them in an area that provides some degree of shelter from the natural elements (sun, wind, rain, etc…) until they can be planted.
Choosing the Right Perennials for Your Location
There are several factors to consider when choosing perennials for your landscape. The most important consideration is the environment that you will be planting them in. Several environmental factors that may affect the performance of perennials include the amount of sunlight (full sun, partial shade, shade) the site receives, the moisture characteristics of the site (wet or dry), and the temperatures the perennials are going to be exposed to during production. Each perennial performs best when it is planted in its preferred environment. Planting perennials in locations with inadequate conditions will greatly reduce their appearance, performance, and longevity. For example, planting a perennial with a full sun requirement in a location that has full shade will reduce the appearance of the plant, decrease the number of blooms produced, and the flowering will usually be delayed compared to the same perennial planted in a sunny location. Also consider the USDA Hardiness Zone designation of each perennial before purchasing and planting perennials into your landscape. This provides an indication as to where each perennial is likely to survive the winter months. Use USDA Hardiness Zone recommendations as guidelines as many factors such as the actual snow cover and moisture levels of each site will also affect a plants ability to withstand cold temperatures. For improved success, choose varieties that are known to perform well in the type of area you desire to plant them in. When planted in a suitable environment, perennials will flourish and provide you with years of relatively maintenance free beauty.
There are numerous ways to utilize perennials in the landscape and around the home. In the landscape, perennials are used as accent plants, border plants, groundcovers, or in mass plantings. They are often used to attract birds and butterflies into the gardens. Many people use perennials as containerized patio plants, in combination planters, or as cut flowers.
Perennial Planting & Soil Preparation
In general, most perennials prefer being planted in sites with well drained soil. The drainage in poor soils can be improved by adding organic matter like, compost, leaves, peat moss, or aged manure. For new perennial beds, incorporate 4 to 6 inches of organic matter into the soil before planting. When transplanting new perennials into an existing garden, incorporate a few handfuls of organic materials into the hole prior to planting. In general, dig a planting hole at least 50% larger then the size of the container you are planting. Larger sized holes should be dug when you intend to mix in organic material. Carefully remove the perennial from the container by holding one hand over the top of the pot and turn the container upside down. Gently tap the bottom of the pot to loosen the root zone from the container and gently pull the pot away. If the container does not easily come off, it may be necessary to squeeze the container until the plant comes out of the pot. Next, place the plant in the hole so the top of root ball is at the same level as the top of the hole. It may be necessary to remove the plant and place a little soil back in the bottom of the planting hole and retry aligning the top of the hole with the top of the root ball. Many perennials do not tolerate being planted too deeply and may not grow very well or may succumb to crown and root rots. Conversely, perennials planted too high may not grow properly and are more susceptible to drying out. Once the plants are at the proper height, fill in the planting hole with soil, gently packing the soil around the roots and being careful to not overly pack or compact the soil around the new planting. After planting, it is important to water them well. For the first couple of weeks or so, it is important to keep the soil moist, but not soaking wet. Keep in mind that many new plantings do not perform well or even die because they are either over- or under-watered. Once they are established, most perennials can tolerate less moisture. For optimum growth, it is recommended to deliver 1 inch of water per week either by rainfall or through irrigation systems.
To optimize performance, improve plant appearance, and ensure longevity there are a few maintenance activities that gardeners should consider. Most perennials can be grown successfully with relatively little maintenance, while other perennials will require more work to keep the in good condition. Although most perennials are not considered to be ‘heavy feeders’, it is important that they are produced with an adequate nutrient supply. Mulching the perennial beds with compost each year often supplies an ample supply of nutrients. In beds covered with bark mulches, it is recommended to fertilize once or twice per year with a general purpose fertilizer. Applying too much fertilizer causes many perennials to grow too quickly and become floppy. Do not apply fertilizer directly on top of the crown or severe injury from the salts may result. Perennials with tall flower spikes or full heavy flowers, such as Alcea or Delphinium, may require staking to prevent them from toppling over following heavy rains and high winds. Several perennials benefit from deadheading, thinning, or cutting them back. Deadheading entails removing the dead flower heads and faded flowers; this practice keeps the garden looking nice and encourages many perennials to continue blooming for an extended period and improves the appearance of the plant. A few perennials benefit from thinning or removing some of the stems from the dense bushy clumps in the early spring which allows more air circulation and reduces the conditions for certain foliar diseases such as powdery mildew. Similar to deadheading, cutting some perennials back after they flower will often rejuvenate the clump by regenerating new growth and may possibly lead to another flush of flowers later in the growing season. Cutting back is also used to prevent some perennials from flopping over or to prevent the centers of the plants from opening up and appearing ragged following bloom. Another important consideration is to prepare perennials for the winter. Do not fertilize perennials after they stop growing in the late summer or early fall. This will allow them to prepare for dormancy rather than encouraging them to remain actively growing. Many perennials go completely dormant (die back to the ground each year) and should have the foliage trimmed back before winter. Removing the existing foliage will make the perennial beds look cleaner and will decrease the likelihood of diseases setting in over the winter months or being carried over and infecting next years growth. Other perennials, such as ornamental grasses, are often trimmed in the spring allowing the foliage to provide some structure to the winter landscape. In northern zones or where tender perennials are being grown (marginal hardiness in your area) it is beneficial to apply mulch after the ground has frozen to help protect these perennials during harsh winters.
Written by Paul Pilon: Perennial Solutions Consulting