Daylilies: Mow them down or dig up and divide

QUESTION: "Are you supposed to mow down daylilies and [ornamental] grasses? If so, should it be done in the fall or in the spring? I planted blue fescue last year and have not mown down at all yet. I also planted new grass this spring but I don't remember the name. I have several daylilies and some are quite old. I have never mowed them." - Pat Nalty
ANSWER: With regard to the daylilies, you can mow them down anytime now, if you wish. An alternative would be to dig them up, divide them and then replant them to increase the coverage. Doing this now would give them a chance to settle in to their new environment during the winter.
When it comes to grasses, annual grooming is all that is needed, usually at the end of winter as the new grass is beginning to emerge.
QUESTION: "I recently planted 25 Old Fashioned Lilacs to enhance an existing hedge after professional removal of some invasive buckthorn. The lilacs are struggling despite watering, fertilizing when planting, etc. Is there something I can do to encourage more growth than just a few leaves at the top of each stem and revive the 6 stems that sprouted a few leaves initially and now are bare?
"We had unusually hot weather for many weeks which may have been a factor. I'd appreciate any suggestions you may have." - Lois Engstrom
ANSWER: The hot weather could indeed be a factor. There is another possibility. If the buckthorn were very close to the lilac when they were removed, the lilac could have gone into shock. You might want to put bone meal around the roots of the lilac to help regenerate a better root system for the following spring.
Now, here's a comment from a reader concerning an answer I gave recently concerning ways to deter snakes. The original question concerned ways to keep snakes away from a camp site and I suggested moth balls.
COMMENT: "I look forward to reading your articles each week, but was a bit unsettled by an answer you gave concerning snakes.
"Moth balls are not the best solution to deter snakes from an area. The snakes are attracted to the area because of the habitat and what it provides for them. They are either finding shelter or food and the best way to deter them is eliminating these things. By eliminating brush piles or dense under story plantings the snakes and their food sources will not have shelter.
"Moth balls do deter many creatures, but they also poison things unnecessarily. Mammals are deterred more often then amphibians (highly sensitive to chemicals) and reptiles.
"I'm not against the use of chemicals, but using them unnecessarily with ill effects on other creatures, including us, sometimes is not necessary." - Michelle Migliore
ANSWER: You are correct in your answer and the solution you describe is certainly a bit more humane and environmentally responsible! I will pass this along to other readers.
QUESTION: "We are starting to build on our lake lot that is mostly wooded. When we go in to fill in the lower areas, how much soil can we add around trees without damaging the tree? Does it depend on the type of tree? We have oak, basswood and iron wood." - Bill Schroers
ANSWER: In my experience, if you put soil at the base of the tree to a depth of more than a couple of inches you risk killing them.
A better idea if you need to raise the level of the ground is to build wells around the trees extending 3 to 4 foot from the trunk and them add your fill dirt outside the wells. You might want to get a local tree expert to look at them before you start.
Remember the roots of a tree extend out towards the drip line, perhaps 20 feet or more and a tree gets most of its water and nourishment from the top 12 inch layer of soil. If you cover that up it can produce dire consequences.
The Plant Man is here to help. Send questions about trees, shrubs and landscaping to For resources and additional information, or to subscribe to Steve's free weekly e-mailed newsletter, go to
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