Dividing Vigorous Perennials

Beebalm (monarda) spreads to form large colonies that need frequent dividing to keep them within bounds and blooming vigorously. Customer photo from Cheryl S. of Copley, Ohio. See the full-size photo in the Dutch Gardens Photo Center.

Community plant sales and swaps are a highlight of the gardening season at this time of year. These events are ideal places for new gardeners to hook up with seasoned veterans and for surplus plants to find new homes.

Perennials that spread readily and those that need frequent dividing make up the core offerings at these events. Vigorous creepers, such as like beebalm (Monarda), yarrow (Achillea), lily-of-the-valley (Convallaria), obedient plant (Physostegia), and common yellow sundrops (Oenothera fruticosa) can easily take over the garden if allowed to grow unchecked. Digging up the colony and replanting part of the population every couple of years keeps each in its allotted space.

Some perennials grow in dense or ever-expanding clumps that eventually stop blooming or simply die in the middle. These include tall phlox (Phlox paniculata), Shasta daisy (Leucanthemum), blanket flower (Gaillardia grandiflora), tickseed (Coreopsis), Siberian iris (Iris siberica) and lamb's ear (Stachys byzantina). Dividing the clump into smaller pieces rejuvenates the original plant and gives you lots of new plants to share with others or to put in other parts of your own garden.

This clump of monarda is ready to be divided.

Dividing and replanting perennials also gives you a good opportunity to replenish the soil. Whenever I move or replace a plant that I've divided, I add a shovelful of compost and a handful of slow-release, granular, organic fertilizer to the backfill.

Early spring is the best time to divide summer-blooming perennials—ideally when they are still dormant or just as they emerge from soil. I try to complete the job before the stems get more than a couple of inches tall. As plants leaf out, it gets trickier to divide them because their soft new growth is susceptible to drying out, wilting, and breaking. That said, there's always a long list of chores for early spring and it's often mid-May before I've divided and moved all the perennials that need it. As long as you make the moves on an overcast day and keep the plants well watered for a couple weeks, most of them will be fine.

Using forks, it's easy to get the clump out. Take a healthy piece for replanting and use the remaining divisions elsewhere—or share them with other gardeners.

I usually start by digging out the entire clump with a garden fork or spade and putting the plant on a tarp to contain the soil and debris. Some plants are easy to pull apart by hand (beebalm), but others take some serious muscle (tall phlox) and the prying action of a couple of garden forks placed back to back. A few are so tough (Siberian iris), that it's tempting to resort to a machete or hand saw to get them apart. Regardless of the plant’s tenacity, I make sure that each division has plenty of roots and several vigorous shoots. A few of the largest divisions go back—into the garden with a thorough watering and the rest get potted up and labeled for the garden club’s plant sale in May.

For lists of perennials that need frequent dividing and more details on how to do it, visit these web sites:

• Dividing Perennials: From the University of Minnesota Extension Service
• Dividing Perennials: From the Clemson University Cooperative Extension Service

-Ann Whitman, Horticulturist

Beyond Pansies

This planter features rose-blotch pansies, pink hyacinths and blue muscari.

There are a few weeks (or maybe a month) in spring when it's too cold for annuals, but nice enough for something. Usually, that means pansies —especially up here in Vermont, where we usually have to wait until Memorial Day to feel safe about putting out annuals. However, you can make a container planting that will thrive despite the changeable conditions of spring.

While looking for planters at the garden center, I noticed a beautiful display of forced bulbs—probably late risers that didn't put on a show in time for Easter. What's more, they were 50 percent off. I selected some pink hyacinths and a few tiny pots of muscari (grape hyacinths) to mix with a six-pack of rose-colored pansies. The result was instantly satisfying. Next year, I might even plan ahead and force my own bulbs.

Don't get me wrong, pansies are great. All by itself, a planter of pansies is lovely—especially with the array of colors and forms that are available these days. But, it's exciting to have more options that look great and perform well during cool spring weather.

I've been enjoying this instant container planting so much that I've decided to use this urn to display a changing selection of plants throughout the season. When the springtime show has passed its prime, I'm thinking about osteospermums (African daisy)... or maybe argyranthemum (cobbity daisy)?

 

-David Grist, Online Content Coordinator

Miniature Daffodils

A Dutch breeder holds some new, unnamed miniature daffodil cultivars.

For the past 20 years, I’ve been adding a few new daffodils to my home landscape every fall. Now, more than 60 varieties bloom in my borders and under trees and shrubs from late March to early June. It’s a show that my neighbors and I look forward to as the snow melts and the days finally get longer and warmer.

Of all the varieties that I’ve collected over the years, I find myself increasingly fond of the miniature daffodils. Smaller versions of full-sized daffodils, these little gems grow only 6 to 8 inches tall and have equally diminutive flowers. Their petite size makes them perfect for tucking into the lawn and rock gardens, planting under shrubs, and mixing with crocus, Scilla, grape hyacinth and other small-stature spring flowers. Unlike their larger brethren, miniature daffodils fade more gracefully after blooming because their foliage is short and narrow and looks less messy and obtrusive as it ripens.

Although mini daffodils are hard to find in stores, specialty catalogs offer plenty of choices. The American Daffodil Society maintains an approved list of 183 miniature cultivars that grow less than 6 inches tall. They recognize 13 different divisions of narcissus based on flower form and the number of flowers per stem. Categories include daffodils with small cups, large cups, trumpet-shaped cups, double flowers, Narcissus species, and others. Every division includes miniatures as well as full-size cultivars.

My garden already included several swaths of yellow Tête-à-Tête and yellow and orange Jetfire, which are the most commonly available cultivars. These early bloomers are the perfect complement to blue crocus and dwarf Iris reticulata. They make wonderful little bouquets, too, and are easy to force indoors for midwinter color.

Encouraged and excited by the success of my first mini daffodils, I added half a dozen new cultivars to my garden a couple of years ago. Segovia is a sweet little flower with pure white petals and a small flat yellow cup. Xit is an all-white, show-winner with a name I can’t pronounce. (Please add a Comment, below, if you know how to say it!) Chiva is a very fragrant jonquil with buttercup yellow blooms. Heirloom Pencrebar hails from the 1930s and has rich, yellow, double flowers. Sun Disc ends the daffodil season with round, fragrant, white-and-yellow blooms.

I’m looking forward to adding even more miniature daffodils in the coming seasons. My favorite source for bulbs is Dutch Gardens, (which is a sister company to Gardener's Supply). Dutch Gardens sells fall-planted bulbs (including miniature daffodils) through the end of October.

-Ann Whitman, Staff Horticulturist

A miniature variety called Tête-à-tête is among the first bulbs to bloom here at Gardener's Supply.