Tracy in Crofton writes: “I heard your advice on using shredded leaves as mulch. Almost all my trees are oaks, and I have read that shredded oak leaves are not recommended for use as mulch because they don’t break down quickly. Is that accurate? My other concern was a warning that shredded leaves are ‘welcome mats for voles'; do you have any comment on that?”
Shredded oak leaves make a great mulch, Tracy. Oak leaves are more fibrous than some other leaves, but you don’t WANT your mulch to break down fast.
Any mulch can provide cover for shrews and voles, especially wood, bark and root mulches, and especially when such mulches are applied too heavily or mounded right up against the sides of plants — an incredibly foolish “horticultural design” that allows rodents to gnaw away at the tasty bark unseen. The way to prevent such problems is to never spread any mulch deeper than 2 inches, and never let any mulch actually touch the trunk of a tree or the stems of a shrub.
And yes, this means that if you have “volcano mulched” trees, you should hoe that mulch away from the trunks ASAP. Piling mulch up against the side of a tree is like handing out knives and forks to the tiny vermin in your yard.
Lilacs blooming in November!
Maria “in Southern Maryland” writes: “I looked out my window today and noticed that my lilacs are blooming. They’re 10 years old, and have never done this before. We’ve had a few frosts already, and everything else is dead. How can this be?”
You’re not alone, Maria. I’ve gotten a handful of reports from our region — and as far north as New York — of spring bloomers like lilacs, azaleas, dogwoods and Bradford pears blooming out of season from the stress of this wretched roller coaster of a spring, summer and early fall.
Don’t do anything to the plants now. Don’t feed them, don’t prune them and don’t mulch them. Enjoy the flowers, and ideally let the faded blooms just remain on the plant over winter.
The affected plants may bloom again in the spring or they may not. Either way, do be sure to prune them lightly after their typical bloom time is over in the spring. Don’t panic or overreact and there should be no lasting damage from this (hopefully) unusual episode.
How to handle an ivy-covered lawn
Kathy in Silver Spring writes: “I had a family emergency and wasn’t able to get out and tackle the ivy that was taking over my lawn this spring; the ivy has since killed most of the grass. Can I kill the ivy with Brush B Gone or something and sow rye grass for the winter? Or do I have to wait and use regular grass seed next spring?”
None of the above, Kathy. No herbicides — including the deadly, dangerous one you name — have any effect on ivy. They just roll off of its protective waxy coating. Like it or not, ivy has to be removed the old-fashioned way: physically. And rye grass seed won’t germinate any better in cold weather than any other type of grass seed.
So use the next 10 months to attack and eradicate the ivy. Break the job up over that entire time. Soak the soil well and pull some of the ivy out — roots and all — every weekend you can work outside. (The colder the weather, the better, in fact. It limits the ivy’s legendary ability to regrow.)
In spring, begin cutting whatever “lawn” you have high and keep working the ivy. Then prepare the soil by adding a lot of compost and leveling it out perfectly before you sow your new seed next August — the only reliable time to sow a new lawn in our region.
What to do with crabgrass NOW?
Nari in Reston writes: “I haven’t gotten all of my over seeding work done yet. I have quite a few big areas of crabgrass and don’t know if I should continue spreading new seed overtop of them in this already cold weather or if I should not. Please advise me on what I should do now and next spring.”
It’s too cold for any seed to germinate now, Nari, and I suspect that any seed you spread over-top of crabgrass was a waste of money anyway. If you want to do something this fall, pull out some of the clumps by hand (soak the soil well first and pull slowly (you’ll get big clumps out in one piece, roots and all) or torch the tops of the plants with a flame weeder to kill some of the seed the crabgrass has recently set.
The actual crabgrass plants you see now will die over winter — the problem is all the seed they drop in late summer. Treat your lawn in the early spring (as soon as the first forsythia bloom) with corn gluten meal, a natural pre-emergent herbicide that will prevent any crabgrass seed you missed from germinating. (It’ll give your lawn a perfect spring feeding as well.)
Then keep the grass cut high over the summer, water deeply and infrequently and don’t feed your lawn in the summer. These correct lawn care tactics should block any new crabgrass from moving back in.
Should you leave lawn clippings lie? (Or is that ‘lay’?)
Lang in Alexandria writes: “Should I leave the grass clippings on the yard every time I cut the grass? Do the grass clippings do much for the yard?”
Well, Lang, you should return the nutrients in your grass clippings back to the lawn, but you should NOT leave VISIBLE clippings on the lawn.
That may seem contradictory, but all it means is that you should be using a mulching mower. These specialized lawn mowers trap the cut blades of grass inside a sealed deck and cut and recut them with a super-sharp blade until they’re returned to the lawn as a pulverized powder.
Bottom line: Covering the lawn with big wet clippings from an old-fashioned mower is bad for your lawn. But the nitrogen-rich pulverized powder from a mulching mower provides half the food your lawn needs every season!