Daylilies & Irises: How To Divide & Transplant
Best Time For Daylilies:
- Best done in the Spring and early Fall to give the plants a few weeks to adjust before the weather becomes extremely hot or cold.
- When doing this in the Fall, at least 6 weeks before the first frost date is a general rule.
- Those with severe winters (especially zones 3 & 4) are at greatest risk of losing plants over the winter, so Spring is a better time to do it.
- In hot climates (for example zones 9 & 10) more plants are lost in the summer months due to heat stress, so dividing in the Fall is a better option.
- The old fashion orange flowering varieties are very vigorous and should be divided every couple of years to prevent over crowding. The newer varieties are not as vigorous and can be left for a longer period of time.
- Try to separate the fans with as little damage as possible to the fan and its roots. Use a screwdriver, serrated bread knife or a hand saw to cut apart the fans at the base or crown. You can try to slice between them with a shovel, or use two screwdrivers prying apart in opposite directions.
- Cut back the foliage by at least half.
- Dig up the entire clump, including about 6 – 8 inches of soil surrounding the clump (many of the roots grow out from the center).
- Wash off as much dirt as possible.
- Find where the fans are connected at the crown of the plant – that is where you carefully cut or pry them apart. Some fans are not connected, you merely need to disentangle their roots. Breakage or cutting of some of the roots is inevitable, but try to preserve as much as possible. If a fan snaps off of the crown, the leaves will not grow new roots. But it is possible that the crown, if the roots are attached, will sprout new leaves.
- Replant each fan at least a foot apart. Dig a hole that will accommodate the roots, and make a mound in the hole so that the crown sits on the mound, just below ground level, and the roots spread out and down from the crown.
- When receiving fans, soak them in water for 2 hours and then plant as soon as possible. If you can’t do so right away, keep them in a cool, dry place. They can be planted Spring through Fall, but no later than one month before the first hard freeze in your area.
- For the best blooming, choose an area that receives 6 hours of sun per day. Dark colored varieties will last longer if given afternoon shade.
- To maintain a healthier plant or to transplant part of a variety to a new location, dividing may be the answer. When the clump (the root area next to the ground) becomes dense, with over 15-20 fans, it may be divided. To do this, dig up the clump and wash off the dirt. Cut the leaves back so that they are approximately 6 inches above the roots. Use a shovel or fork to gently break the fans apart. The most desirable transplant size is 2-3 fans.
Best Time For Irises:
- Late July or early August is the best and they should be dug and divided every few years to prevent them from over crowding.
- After digging the roots or rhizomes, remove the segment with leaves from the older segments. This is the current seasons growth and is the portion of the plant which is kept and reset. Always discard any which are weak or diseased.
- Set the divisions in a hole large enough to easily accommodate the attached fibrous roots. The top of the rhizomes should be level with the soil surface. Firm the soil down well around the divisions, cut the tops back to 6 inches and water in well.