When is the best time to divide my hostas? Gwen, Tulsa
If hostas need division, they can be divided either in early fall or spring as soon as new leaves emerge. Fall dividing may be preferable, but spring is also acceptable.
A general rule for division of perennials is to divide the spring-blooming plants in the fall and the summer- and fall-blooming plants in the early spring. Dividing when not flowering allows energy to be directed to growing new roots.
Some of the many plants that may be divided in the spring are hostas, asters, astilbe, gaillardia, black-eyed Susans, cannas, garden phlox, mums, coral bells, daylilies, purple cone flowers and tall sedum. Most of the ornamental grasses are also best divided in spring.
Not all perennials need dividing, but many will either outgrow their allotted space or multiply and become so dense in their centers that blooming suffers or they become susceptible to diseases. When the center of the clump becomes barren, it is time to divide. Another good reason to divide any perennial is to get new plants for your garden and to share with fellow gardeners.
After deciding to divide, wait until the plant shows evidence of new growth in spring. Water the plant well one to two days before digging and prepare the new bed. Work in some good rotted manure or compost in the new bed, and then water to keep it moist. Adding a slow-released balance fertilizer to the soil would also be an option.
Dig the perennial with as large a root ball as possible and divide. You may need a sharp knife or hatchet to divide clumps, especially ornamental grasses with tough root balls. Be sure each division has three to four stems or leaves above ground and a generous amount of roots below. Do not let the roots dry out; keep a pail of water nearby to moisten the roots, if needed.
In the new hole spread the roots out and cover with soil. Most perennials should be replanted at their original depth. Water the new transplant well to establish good soil-to-root contact and mulch. Mulch will help conserve water, keep the bed weed free and control temperature extremes.
Dividing perennials not only improves the health and appearance of your garden, but it is also an excellent way to be a good neighbor.
The Tulsa Master Gardeners are volunteers who provide information to home gardeners. See tulsaworld.com/mastergardener
or call 918-746-3701 for garden-related questions.
March gardening tips
Plant cool-season vegetables now. All leafy vegetables, carrots, beets, onions, potatoes and others should be planted early this month.
February and March is the best time to plant strawberries in our area. It is important to select and prepare the site properly and choose the best strawberry types for Oklahoma. Obtain OSU fact sheet "Growing Strawberries in the Home Garden" for complete information at tulsaworld.com/growstrawberries
Fescue lawns may be seeded or reseeded in March, but September is the best time to seed. Fescue, which germinates in spring, generally can't establish an extensive enough root season to cope with the summer heat. Generous irrigation is needed.
Original Print Headline: Hostas can be divided now
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