When should you plant perennials? Perennials thrive when planted in the spring (March to early May) or fall (late September to October), when the soil is wet. They don't like to sit in cold soil, so keep that in mind if you're planting in April or October. You can also plant them in late summer (August) or early winter (December). The plants will go into dormancy naturally when the weather gets colder, but you can help them along by covering them with something for at least two weeks after the last frost.
Hardy perennials need to be planted in areas where they can get full sun and average temperatures of 50 degrees F or warmer. They come in a wide variety of shapes and sizes, but they all have three things in common: flowers, seeds, and foliage. All hardy perennials make new growth in one area of the plant, then stop. This is called a dormant period. During this time, the energy stored in the stem and leaves will feed the development of buds which will eventually become flowers or fruit. When you plant these hardy perennials, try to choose a site where they will get 6 hours of direct sunlight and average temperatures of 50 degrees F or warmer. This will help them grow healthily.
Planting in the spring and fall, when the temperature is cooler, has long been the rule of thumb. However, if the plant has spent the previous few months in a container, you may effectively plant fresh perennials, annuals, and shrubs in the heat of summer. The key is to provide plenty of water so they don't die from drought. If you wait until winter, then you will need to protect them from freezing temperatures.
The best time to plant shrubs is in early spring before the first flowers appear. This way, their roots have time to get used to Earth's natural climate before the hot sun beats down on them and causes them to wilt. You can also plant in the fall if the ground isn't frozen yet. But be aware that some plants will grow faster if planted in the spring; others will do better if you let them go into dormancy over the winter and then plant again in the spring. And still others should never be moved or transplanted because they won't survive being taken out of their natural habitat.
Some plants are sold as "half-hardy" or "semi-hardy". These are terms used by gardeners to describe plants that can be exposed to at least half of their maximum winter temperature without dying. Full-hardy plants can withstand cold temperatures typical of low-lying areas near buildings or where there is no soil protection at all.
Perennials exist in a wide variety of forms, sizes, and colors. One of the nicest things about perennials is that they only need to be planted once and then grow bigger and better each year. Many perennials may be split every 3–4 years, giving you enough to put elsewhere in your garden or give with friends.
Some types of perennials may even be divided every other year or so. This is a great option for gardens where space is limited or money is not an issue because it means fewer plants are needed than annuals. Perennials that can be divided include geraniums, lobelias, salvia, and scented plants such as roses and verbena.
Other types of perennials do not divide themselves but can be divided. These include bulbs, corms, and tubers. Divide bulbs every year or two after they have been grown for several seasons just like regular bulbs and then add them to new areas of the garden. This will keep the size of the plant consistent and allow more to be planted if desired. Corms and tubers should be divided before they are established since this will prevent future growth. For example, if you wanted to divide up a potato bed each time you dug it over, you would want to start with new pieces of soil. This will help ensure strong roots from each portion of the plant.
Finally, some types of perennials cannot be divided.
Perennial plants grow in the same place year after year. Because perennials' roots are more extensive than the roots of annual plants, they require less maintenance in the form of watering and fertilizer once established. Many perennials expand quickly, filling up garden areas and adding color year after year. Perennials remain in the ground longer than annuals because they are usually selected for their durable flowers and foliage which resist heat, cold, drought, and other adverse conditions better than their more floriferous counterparts.
Some perennial plants may be divided before planting or pulled out by the roots if they become too large or invasive species. This is called "division" or "root pruning." It can be done with bulbs, corms, and tubers. With these types of plants, only a few sets of roots will come up under any one plant. The rest of the roots will spread out over time, helping to keep soil enriched with nutrients. If all of the roots are removed, new shoots will develop from within to provide new plants for next season's garden.
Some perennials, such as hostas and daylilies, are grown as ornamentals for their colorful leaves and flowers. They are not eaten as food and so do not need to survive winter.
Others, like geraniums and petunias, are used in gardens for their beautiful flowers.
The months of April and May are ideal for beginning landscaping and planting trees, shrubs, and perennials. These spring months will allow your plants to flourish and adapt before the summer and fall. The next optimum time to start landscaping is in the fall. The ground is not as warm then, but there are no flowers or leaves on the plants so they do not hinder your work.
The least favorable time for landscaping is at the end of June when most gardeners finish planting for the year. By then, the temperatures are rising, weeds are emerging, and everything needs to be watered regularly. Beginning in September, the weather begins to turn cold and plants need protection until the following spring. There is also a risk of damage from ice and snow during these winter months.
The ideal time to landscape is every month of the year! If you don't take care of your yard during off-season, it will require more maintenance and cost more money to keep it looking good. But don't worry, that's why they call it "landscaping," because it's always changing something!
Landscape professionals recommend creating a plan first, then taking measurements to make sure you're not covering any underground utilities like water lines or power cables. After the site has been graded and prepared, plant species that tolerate both dry conditions and wet conditions are best.