If you were disappointed in the quality of your daylily blooms this year, it may be time to divide. Daylilies need to be divided every three to four years to maintain vigor. This is the best time of year to divide them, but they can also be divided in early spring before growth starts. Many gardeners cut back the tops to about half their original height to make plants easier to handle.
Daylilies have a very tough root system that can make them difficult to divide while in place. Dividing in place is practical if it hasn’t been long since the last division. In such cases, a spading fork can be used to peel fans from the existing clump. If the plants have been in place longer and are well grown together, it is more practical to divide them after the entire clump has been dug.
Use a spade to lift the entire clump out of the ground. Although it is possible to cut the clump apart with a sharp spade, you’ll save more roots by using two spading forks back-to-back to divide the clump into sections. Each section should be about the size of a head of cauliflower. An easier method involves using a stream of water from a garden hose to wash the soil from the clump, and then rolling the clump back and forth until the individual divisions separate. Space divisions 24 to 30 inches apart, and set each at its original depth. The number of flowers will be reduced the first year after division but will return to normal until the plants need to be divided again.
By: Cassie Homan
If your irises aren’t looking healthy this year, they may have a condition called bacterial soft rot. The bacteria will cause a smelly and slimy rot of the leaves and rhizomes. Leaves often separate easily from the rhizome. If your plants are heavily infested they may die.
Though most often associated with iris borer, environmental damage can also provide an entry point for this disease.
Rhizomes that show extensive signs of damage should be discarded. If there is a plant that has special value, you may wish to try to save it. The American Iris Society suggests using a spoon to remove all infected tissue. Then, allow the rhizome to dry in the sun. Finally, use a chlorine based cleanser to powder the wound. Dousing in place with Dial antibacterial soap (with triclosan) can be substituted for the chlorine based cleanser.
When dividing rhizomes from beds that have shown evidence of soft rot, disinfect the knife between cuts of even apparently healthy rhizomes with a 10% bleach solution or rubbing alcohol.
As mentioned previously, iris borer damage can provide a place of entry for this disease. To control iris borers, remove and discard dead leaves in the fall to eliminate a number of the iris borer eggs. Larvae can also be killed by hand in June by squeezing infested leaves in the vicinity of the injury. During division, borers in lightly infested rhizomes can be killed by poking them with a piece of wire. Borer control can also be achieved through the use of imidacloprid (Merit, Bayer All-In-One Rose & Flower Care, Bonide Systemic Granules, Hi-Yield Systemic Insect Granules) or through the use of the parasitic nematodes Steinernema carpocapsae or Heterorhabditis bacteriophora.
By: Cassie Homan
If you have been disappointed by your annual flower beds or containers in past seasons, try our tested varieties. K-State has tested annual and perennial flowers for many years to find the best of the best. These colorful blooms are sure to stand up in our summer heat, and hot winds. Use the Prairie Star website as a shopping list when picking out your flowers this spring.
Prairie Star Annuals and Prairie Bloom Perennials Website:
By: Cassie Homan