Perennials bring beauty to our gardens for years at a time. All they ask for in return is proper care! Part of that care is cutting back perennials at a minimum once a year. This process rids perennials of their old foliage to make room for new growth and flowers.
However, there are cultivated plants which are more susceptible to problems if the old foliage and dying stems are left to rot. Diseases can overwinter in dead foliage, as can slugs and other pests. Old stems can also get battered about by fall and winter winds, which will damage the plant's crown and roots.
It's common to think that everything should be chopped down to the ground in the fall, but some perennials actually need their foliage to protect new shoots through the winter. Other varieties offer up important habitat for local wildlife and some perennials provide height and interest through the winter months.
Many gardeners cut back their perennials much too soon. There are nuances specific to certain perennials that dictate whether it is better to cut them back in fall or spring, but the general rule I like to follow is to only cut back perennials that start looking bad in fall.
2. Perennials and shrubs that are in your zone or one colder can be overwintered in an unheated garage, buried in the ground, or transplanted. 3. Perennials and shrubs in containers will need water through the winter but should not be kept wet.
Some perennials keep their leaves through winter, like spring-blooming groundcovers, Heucheras, Hellebores, ferns. These are trickier. Spring groundcovers, like Candytuft and Basket of Gold should be sheared after blooming. Ferns and Heucheras should be cut back in late winter before new growth starts.
Some perennials, like hostas, peonies and daylilies, need to be pruned in fall to avoid winter damage. Plants like these should be pruned after the first few frosts in late fall or early winter. Other perennials like mums and coneflowers are better off being pruned in spring just before new growth comes in.
The process of trimming back plants is the same for nearly all perennials. Begin by cutting the plant back to 3 to 5 inches above the soil line. Using a sharp pair of pruners or hedge trimmers, cut off all of the foliage and stems. Cut the plants down to within three to five inches of the soil line.
Pruning Perennials – General Pruning
In early spring, old foliage should be removed from most plants. Many spring blooming perennials should be pruned just after the blossoms fade. Perennial plants which bloom during summer and fall should be pruned in spring to create bushier, more floriferous plants.
To prevent the disease from returning the following year, we suggest cutting the plants back in the fall and removing any debris – no matter the variety! It will give your plants a clean start next season. *Destroy any foliage with symptoms of powdery mildew and disinfect pruners before trimming other plants.
Transplant perennials when the weather is cool, even a little rainy, if possible. Early spring and fall care are best times for transplanting. Then the weather is cooler and the plants are not using as much water. “However, don't move or transplant perennials while they are in bloom,” he says.
A couple of drawbacks to perennials are their longer yield times, with some taking years to bear a full bloom or crop. Furthermore, they can also be more susceptible to disease and are known to require more space than annuals.
After a few years in the garden, these perennials may start to produce smaller blooms, develop a 'bald spot' at the center of their crown, or require staking to prevent their stems from falling over. All of these are signs that it is time to divide.
Don't Divide These Perennials
Some plants resent being divided and it should be avoided if possible. These include butterfly weed (Asclepias), euphorbias, oriental poppies, baby's breath (Gypsophila), gas plant (Dictamnus albus), Japanese anemones, false indigo (Baptisia) and columbines (Aquilegia).
Prune lilies in the fall or early spring to remove spent foliage. Wait until the foliage has completely turned brown and limp, and then cut all top growth to the ground. Pruning lilies too early before the foliage has a chance to die back can prevent the bulb from storing adequate energy for winter.
Perennials come in all shapes, sizes, and colors. One of the best things about perennials is that you only have to plant them once and then they come back bigger and better every year. Many perennials can be divided every 3-4 years, so you'll have plenty to plant in other parts of your garden or share with friends.
Often, the center of the clump will begin to die. These are all signs that the roots and stems are crowded and the plant needs to be divided. The general rule of thumb is to divide perennials every three years. However, this depends on the perennial and its location.
Overwintering Techniques
The general consensus seems to be that the best way to overwinter containerized perennials is to take the entire pot and bury it in the ground. This way, the roots are protected like they would be if the plants were actually planted in the garden.
Lavender is a perennial herb in many areas - that is, perennial if it gets really good drainage. Growing in a pot is an ideal way to provide good drainage. However, if the potting mix is extremely fertile, the plant may grow leaves and stems rather than flowering.
After a perennial geranium has spent the season in bloom and begins to die back, you'll want to prune it. This keeps the plant dormant for the winter and also helps it store energy for spring. Depending on your zone, this might need to happen anywhere from August to late October.