uhmm well, im not sure pruning is the answer. perhaps you need to move them.

daylilies do not need to be trimmed. and for best results, shouldnt be. especially when the foliage is still green. plants actually feed on their own foliage and use its energy for propagation, root stimulation, overall health, the next bloom, etc.

so if your plants health, and performance over rides your need to not encroach onto your neighbors turf...then you should probably just move them.

if its not so important to you and you absolutely want to trim them...then cut them back to 5-7 tall in the shape of an upside down V. make em look like arrows or spears that point up. however, keep in mind that the longer you wait to move them, the more they will spread...and the bigger the initial problem will get.

also, im not sure what type of daylilies you have, they may be evergreens. which means the foliage will always be relatively green. certain older leaves may die off which you can pull if you like, but the clump as a whole will remain.

This post was edited by taurustendency on Mon, Oct 14, 13 at 7:15

Daylilies will continue to send out new leaves from the middle and shed the older outer leaves, especially during times of stress. Unless you are transplanting them, it neither hurts nor helps them to have their leaves trimmed back about half way, it just makes them tidier looking. If you are just concerened with the part hanging over the driveway, then have no fear and pull out or trim off anything that is overhanging. The plant itself will be just fine and will not complain over the loss of some of its green leaves.

As the above poster said tho, that is merely a temporary solution. In a month or so its new leaves will again be overhanging so you may want to divide it or just move it back from the driveway a bit. Daylilies are very forgiving plants, so you can dig it up with a gardening fork (preferred to a shovel so you keep more roots intact) and replant it at the same depth. Be sure to water it in after replanting if you choose to go that route and keep it watered every day for a couple of weeks so it can re-establish itself.

Debbie