IN THE GARDEN: Now’s the time to divide perennials

Tuesday, August 28, 2018 - 14:34
  • Summer Holt places soil and compost onto a perennial bed at the Alaska Botanical Gardens during United Way’s day of caring campaign Thursday, Sept. 14, 2017. Holt, a BP employee, participated in the half-day of volunteer work with a few dozen of her co-workers. (Loren Holmes / Alaska Dispatch News)

Now is a good time to divide your overgrown perennials to ensure healthy vigorous plants that will continue to bloom for you year after year. As a bonus of dividing perennials, more plants are made to keep and expand your garden or share with others.

As perennials mature and become larger, their roots become crowded and they will find it increasingly difficult to absorb nutrients from the soil. This decrease in nutrient uptake results in less growth of foliage on top and eventually less energy to produce blooms.

Plants can be successfully divided when the plants looks their best and are not in active growth, usually in late summer after blooming. Try not to wait until the plant becomes huge and starts deteriorating and grow ing into your other plants.

To divide the plants, use a gardening fork to gently lift them starting at the drip line. Roots will generally extend out past the drip line of the plant. When using a fork or a shovel, dig a trench around the plant clump. Don’t be afraid of cutting off any roots that may extend outward. Cut under the clump at an angle down and under the plant at different points around the plant until you are able to lift the plant from the hole.

It’s best to divide when the temperature outside is about 50 degrees and plan on keeping these roots cool and moist. I place mine in a bucket of water if they are not immediately planted to allow them to drink for 24 to 48 hours in the shade before replanting. Placing the plants in a plastic grocery bag works well also and gives you a handle to carry them.

When transplanting your divided plants, amend the soil by putting a generous supply of compost in the new hole. If you have your own compost pile or need to purchase bagged compost, this new loose soil will help roots re-establish themselves quickly before the ground freezes.

One of the most important factors in transplanting success is water. Immediately after planting, settle in the plant with a good watering. Don’t be alarmed if your plant initially loses some of their leaves, or if the leaves become wilted as this is normal. You will want to water this transplant about three times per week to keep it moist. In about 3-5 days your transplanted plant will perk up again as it gets used to its new surroundings.

Lilies grow well for us here and a plant that will need to be divided over time. One of the secrets to keep lilies blooming is to divide them in late summer. Most bulb plants go through a process called naturalization when the plant produces more bulbs which mature and grow underground. The original bulbs will subtly decrease in flower production overtime and the new bulbs will take over the role and become the center of attraction.

Dividing lilies and transplanting is easy and can usually be done about every 2-3 years. When you notice the foliage start to yellow, this is a good time to transplant. Cut the stems down to 5-6 inches above the ground and gently lift the plant out with a gardening spade fork. Carefully separate each bulb cut off the smaller bulbs on the chain. Quickly replant these smaller bulbs so that they do not dry out. Plan to have your place to put the bulbs and have the hole dug and ready to go. Lilies look best in groups of 3 or more. Space each bulb 8-12 inches apart giving them ample room to stretch out and thrive. Plant your new small bulbs under a few inches of soil and insulate the bulbs with several inches of mulch and plan to pull this mulch back in spring as the lilies emerge.

Hostas, another great plant for us, grow quickly and I was able to divide them making 12 plants of 2 clumps very easily. After three years these plants are ready to be divided again. If you wait too long, you will notice that the center of a large clump of hostas will start to die out. Dividing every three to four years is optimal to keep these plants healthy and vigorous.

Fall is the best time to divide your hostas when it is cool and humid. A four-week window is needed before the freezing of the soil to get these beauties planted. Hostas like dappled shade areas of your yard.

Prepare the transplant holes ahead of time again with fresh compost to nourish the new plant. When you dig up your hostas clump, you will see that your plant is made up of several individual hostas plants. Carefully break apart the plant leaving 3 shoots together to form another plant.

Growing your garden is easy and economical when you divide your perennials to fill out your yard. The time is now to perform this magic. Enjoy these last weeks we have left working in the garden. Go bold and divide your plants to keep them healthy and vigorous and I know that you will be very pleased at the results. See you around town.

Chris Wood is president of the Greater Eagle River Garden Club. Write to her at [email protected]

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