Lilac bush in distress - how to revive? archived

Too late for this year.

You should prune off dead flowers after they wilt in the spring. Around Memorial Day or early June is best.

You should also prune the plant generally to keep it healthy. Rule #1: Never prune more than a third of the total plant.

Pruning the "sucker shoots" near the base of the plant keeps the mildew minimal (but mildew is natural on Lilacs and not to worry). Prune branches to keep the overall plant airy - that means pruning away some of the larger interior branches.

You'll have a lovely plant next spring.

You should remove the old canes while the plant is dormant and lime the soil to correct the ph.

I have always heard that lilac trees/bushes were extremely hardy and never needed pruning. False information, I guess? I read this in a gardening book.

we pruned our lilac in early March - cutting the last half of the old wood down to 18". the stems were more like trunks.

We already have sprouts. Last year we did the same.

We realize it means no flowers this year - but hopefully next.

Also our soil is very acidic - bury chalk in the ground around the roots.

Posted By: TiliaYou should remove the old canes while the plant is dormant and lime the soil to correct the ph.

Good point - the major pruning should be done off-season.

why lime?? people just assume that liming every year is needed. But think of it, if you lime every year it just builds up in the soil. The whole point of liming is to raise the PH of the soild. Take a soil sample first to see if you ph is at a point where liming is needed. otherwise all the years of liming have most likely made your soil lean toward the basic side of the PH scale. Your soil doesn't reset to a previous composition after ever year.

I never lime my lilacs, and they've bloomed nicely here in Maplewood for over 10 years now...

i have 4 beautiful dark purple lilac trees...they are about 8 or 9 feet tall and have profuse flowering. the thing that irks me about these trees is that they are very leggy and it doesn't help that most of what needs to be pruned yearly are on the lower inside. i have always cut away the shoots coming up from the roots but i'm wondering if i should leave them this year and maybe they will fill in all the empty space below the crown of the tree. otherwise, i plant hyacinth bean vines at the base of each tree to fill in and over the trunks and to offer some pretty flowers well after the lilacs have faded.

Pruning larger branches and encouraging one or two of the smaller low ones will make it bushier over time. It takes a few years for this pruning technique to bring a large, leggy lilac back down to shorter and bushier, but it can be done.

A visit to an arboretum that has lilacs can provide some insight into how they care for theirs. (I learned a lot from the Arnold Arboretum in Boston...not an easy trip from here!)

Oldstone, you could also plant a clematis at the base of the lilacs and let it climb.

Is clematis the pretty purple flower that grows on a long thin winding vine, and it seems to kill everything around it? Or I assumed it was killing everyting... every time I see it wrapped around another bush or plant I cut it down, and think, too bad the pretty purple flowers are just these scavengers... am I wrong?

re: liming - also, if the lilac is right next to the foundation, the soil may already be alkaline, so have it tested before messing with the pH.

wrt to maintaining lilacs, or rehabbing ones that have gotten leggy, or so tall that the flowers are out of reach, the usual drill is to cut 1/3 of the big, old trunks back to the ground (or close) each year for 3 years. Prune in the spring after bloom (or earlier if you don't mind missing some bloom for that year). Let the "suckers" grow to fill in. This gives you a much "bushier" bush, and flowers you can reach. Don't prune (anything) after Aug 1 or so, to avoid having tender new growth damaged by freezing.

Sometimes, too, lilacs just have an off year for flowering, then are fine again the next year. The powdery mildew looks bad but doesn't harm the plant unless it's already weakened.

enjoy!

Huh. I have a 5' lilac in the front yard, haven't touched it in five years, and it's nice and full and round and blooms profusely. Guess I've just been lucky so far.

Posted By: gilliankaIs clematis the pretty purple flower that grows on a long thin winding vine, and it seems to kill everything around it? Or I assumed it was killing everyting... every time I see it wrapped around another bush or plant I cut it down, and think, too bad the pretty purple flowers are just these scavengers... am I wrong?

I think you might be wrong. Many gardeners choose clematis to pair with other flowering plants. They'll plant a clematis that blooms at a different time and the pretty purple looks like it's the same plant blooming again, with another flower because the vine is so intertwined with the branches.

I've never heard of clematis killing anything, but some people let it grow on a dead or dying plant to add interest. I say let it grow, just at plenty of fertilizer at the base so that both plants have enough nutrients.

peggy, "if it ain't leggy, don't prune it"? Lilacs we have inherited on moving into various houses have mostly been 8 -12 feet tall and scrawny. The renewal pruning made them bushy again, but i've gotta say i miss the hanging-over-the-garage look...

happy weekend!

When we moved in, someone told us that our lilac was a Korean lilac, which might account for its shape? I don't know. But it's beautiful, so I don't question it too much. :wink:

Yes, the Korean ones stay lower and rounder, and they're beautiful too, AND i don't remember seeing the powdery mildew on them. does yours ever get that?

Not that I've seen. On the other hand, a peony that's only about three feet away from it DOES get the powdery mildew. It doesn't seem to do it any harm, and never spreads, so I try not to worry about it.

peggy says: "I try not to worry about it."

good plan, widely applicable

Posted By: mjcgood plan, widely applicable

Well, there's one problem with that approach: Sometimes the plant still dies on me, occasionally when I'm not looking often enough. Being a casual gardener has its drawbacks.

Gillianka- Sounds like you mean Wisteria

seagull,

I thought Gillianka was talking about Jackmanii Clematis, since wisteria don't bloom if you cut them back like that. Trust me, I know something about wisteria not blooming.:cry:

Easy way for Gillanka to tell the difference: wisteria twine around with wrapping vines and have leaves that look like a fern, clematis sends out tendrils that wrap around, they send out two that are on opposite sides of the vine. The clematis leaves are more heart shaped, and the flowers look very different from the grape like clusters on a wisteria.

Wisteria will kill things.

And wisteria vines are pretty hefty, no? They can get as thick as small tree trunks.

I was definitely talking about clematis, as the photo confirms. I had no idea I'd been killing a good flower. It wraps so intensely around everything else that I assumed it was a killer. Now I know.
Is it too late now, mid October, to prune my lilac bush by 1/3?

Thank you everyone for your help.

I would wait for spring, prune soon after it's done blooming. That's a good rule of thumb for most flowering shrubs. Here's a useful link:

http://www.gardenersnet.com/lilac/lilac02.htm

If I trim the suckers now will they die? I think I've been pruning the sucker wrong. I read that they'll double if you cut them too close to the ground, but if you dig down and cut them at the roots they won't grow back. I've got more now than I did last year from this pruning, so I'm either going to have to dig up the whole bed to get them down low, or maybe I'll prune them now when the plant is dormant and prevent re-growth.

Any advice?

Remember clematis vines look dead and woody off season, an amazing quality that takes some getting used to. Could that be what makes them look like killers?

j_b, are you talking about lilac? If so, do you want to cut the suckers? Are you going for a "standard" or tree appearance with your lilac? my understanding is that the "suckers" are what keeps it bushy, and what you cut out is the old stems, not the new ones. But I've always had old lilacs in need of rehab, not new lilacs, so ??

I thought I read that you only wanted lilacs to have 3-4 main stems, and you should cut back the suckers. That's what I've been doing anyway.