Dividing Perennials

Wednesday, November 20th, 2013 by Jenny Watts
    • Fragrant Paperwhite narcissus will bloom indoors by Thanksgiving if planted now in rocks and water.
    • Plant pansies, snapdragons, stock, calendulas and primroses now to replace summer annuals.
    • Plant lawns now to have them ready for next summer enjoyment. Ask at your nursery for the best grass seed for your situation.
    • Garlic sets can be planted now for an easy crop that you can harvest next spring. Choose from hard-neck, soft-neck or Elephant garlic varieties now available.
    • Compost your leaves as they fall, don’t burn them! Leaves make wonderful compost that breaks down into rich humus by next summer.

Divide and Conquer

Fall is a great time to rejuvenate the perennial border by dividing old clumps of perennials to keep them vigorous and blooming freely.

In general, summer bloomers should be divided in the fall, and fall bloomers divided in the spring. Grasses and bamboo should be divided in early spring just as growth begins. Most perennials should be divided every three to five years, but some, like peonies, are best left alone, as it will take them several years to begin blooming again.

Perennials need dividing when the flowers are smaller than normal, the centers of the clumps are hollow and dead, or when the bottom foliage is sparse and poor. Plants that are growing and blooming well should be left alone unless more plants are wanted.

Water plants thoroughly a day or two before you plan to divide them. Prepare the area where you plan to put your new divisions before you lift the parent plant. Prune the stems and foliage to 6 inches from the ground in order to make the job easier and to cut down on moisture loss.

Dig down on all four sides of the plant, about 4 to 6 inches away from the plant. Pry underneath with a spading fork and lift the whole clump. Shake or hose off loose soil and remove dead leaves and stems. This will help loosen tangled root balls and make it easier to see what you are doing.

Perennials with spreading root systems include asters, bee balm, lamb’s ear, Black-eyed Susans and many others. They often crowd out their own centers and can usually can be pulled apart by hand, or cut apart with shears or a knife. Discard the old woody center and replant the young, healthy pieces.

Clumping perennials grow toward the outside of the clump creating new growing points. Many, like astilbes, hostas and daylilies, have thick fleshy roots. It is often necessary to cut through these roots to separate the young plants. Keep at least one developing eye or bud with each division. If larger plants are wanted, keep several eyes.

Bearded iris grow from rhizomes and they need to be divided when they have stopped blooming well. Discard old sections and keep divisions with one fan of leaves, trimmed back halfway. Replant with the top of the rhizome just beneath the surface of the soil.

Plants that have very tough, vigorous root systems, like agapanthus, red-hot pokers and ornamental grasses, may have to be divided with a shovel or saw. You can also hose off the soil to make the root system easier to work with.

Plant the divided sections immediately in the garden or in containers. Replant divisions at the same depth they were originally. Firm soil around the roots to eliminate air pockets and water well after planting.

Fall is the best time to divide most perennials because air temperatures are cool and soil temperatures are warm. So take advantage of the mild fall weather to revitalize your perennials.

Putting the Garden to Bed

Monday, October 26th, 2009 by Jenny Watts
    • Tulips can paint the spring garden with almost any color you choose. Plant them now to enjoy their bright flowers next April.
    • Wildflower seed broadcasted with the first rains will take root over the winter and burst into flower next spring.
    • Garlic sets can be planted now for an easy crop that you can harvest next spring. Choose from hard-neck, soft-neck or Elephant garlic varieties now available.
    • Compost your leaves as they fall, don’t burn them! Leaves make wonderful compost that breaks down into rich humus by next summer.
    • Choose shade trees for fall color now and plant them while the soil is still warm.

Putting the Garden to Bed

Fall is a glorious time of year to work in the yard. It is the ideal time to take stock of your perennial gardens and correct mistakes and problem areas, dig up, rearrange and divide existing plants, add new perennials and shrubs, and plant spring blooming bulbs. As fall winds down and this work is completed, you will turn to the task of putting your garden to bed. Completing a few simple tasks now will not only prepare your garden to withstand the winter but also help plan for next spring.

In the vegetable garden, remove any dead plants and place them in the compost pile. Then turn the soil and plant a winter-hardy green manure crop such as crimson clover, fava beans or annual rye grass. Another option is to turn the soil and then spread a thick layer of compost or shredded leaves on the bed. Both methods will protect and improve the soil over the winter. By preparing the beds in the fall, you can take advantage of the first available planting days in late winter and early spring to plant early peas, spinach, cabbage and lettuce.

Divide artichoke plants which have been in the ground for three or four years. Mulch established plants with steer manure. Garlic should be planted now for an easy crop that you can harvest next spring. Tree collards can be planted now for a delicious winter vegetable.

In your flower beds, wait until perennials have died back before cutting them back almost to ground level, and compost the cuttings that aren’t diseased. The rule of thumb is: “If it’s yellow or brown, cut it down, if it’s green, leave it alone.” Plants that remain green through the winter can be cut back in March when they begin to grow again.

Don’t cut ornamental grasses back until late winter or early spring. Wait until new growth is beginning to emerge from the base of the plant. The stems of perennials like black-eyed Susan, purple coneflower, ‘Autumn Joy’ sedum and grasses add winter interest to the garden, and their seeds provide food for wintering birds.

This is a good time to divide overgrown perennials. It’s also a good time to choose and plant some new varieties, and be sure to add some spring-flowering bulbs like daffodils and tulips.

Remove the leaves of hostas, daylilies and agapanthus as these tend to turn into a soggy mess by spring and provide shelter for slugs. Rake up fallen rose leaves and remove them from the garden area as they frequently have disease spores.

Dig up dahlia bulbs when they are finished blooming. Begonia bulbs should be lifted if they are in the ground. If they are in containers, you can cut back the foliage after frost and store the pots in a dry, frost-free area.

Preparing the garden for the winter ahead ensures that it gets off to a good start next season. Come the spring, when you have so much work to do, you will be glad that your garden is clean and ready for a new year.