DEALING WITH DISEASE: VERTICILLIUM WILT

Given that I delayed a lot of garden work in fall, it's no surprise that the first real job I did in the garden this spring was a task I should have taken care of several months ago. And it was that much more painful for having waited.

Last September I shared the sad news that one of my favorite plants had been hit with a nasty disease: verticillium wilt. I watched as my Lemony Lace elderberry (Sambucus racemes) wilted one chunk at a time, and just when it was finally getting to a good size after three years in the ground.

Verticillium wilt is a nasty soilborne disease that affects many plants (here's a list), including elderberries. Last year I cut off the affected branches, making sure to disinfect my pruners) but I knew when I did it that wouldn't solve the problem. The only real remedy for dealing with it is to dig out the plant and a large area of soil around it.

With those beautiful fat buds, it was even more difficult to dig my Lemony Lace elderberry out last weekend. 

Taking that step last weekend was even more difficult because there were lovely fat buds on the branches that I knew would turn into gorgeous feathery leaves. And they would look good for a little bit but it's likely that they too could succumb to the disease. Or maybe not. According to the Missouri Botanical Garden, the symptoms might not show up this year: "The initial symptoms may occur on only one branch or may involve the entire plant. Oddly, following the initial symptoms, there may be no sign of the disease for several years even though the infection continues to reduce plant vigor."

There aren't a lot of good ways to get rid of verticillium wilt once you have it. You can attempt to solarize the soil by covering it with plastic and "cooking it" it several months—six or more, which isn't a very practical solution in a packed garden. I decided to dig out the entire plant and as large and deep of an area of soil that I could. All of that went immediately to the burn pile.

I don't see solarizing that area as practical for me, but I'm considering giving it a good burn with the weed torch. I don't know that that will work, but I don't think it can hurt.

The elderberry looking gorgeous last year with freshly leafed-out foliage.

I have another Lemony Lace elderberry in another part of the garden that was much more immature but by the time I went looking for it last spring it looked like there was a chance it too had the disease. I haven't yet dug that one out. By the way, I asked the folks at Proven Winners who developed that plant if it was particularly susceptible to verticillium wilt and they said no more than any other elderberry. So I wouldn't hesitate to plant it if you don't have problems with other elderberries.

One of the plants that is susceptible to the disease is Viburnum and my garden is full of them. In fact there is a group of three large Viburnums not far from the elderberry I dug out and one was looking not quite right last year. I'm keeping a close eye on it but already I can see it doesn't have the same flower buds that the others have. I'm crossing my fingers it's not verticillium wilt that's causing the problem.

The optimistic gardener would look at this as an opportunity to plant something new in that spot that is resistant to verticillium wilt. I'll get there eventually, but I'm still sad this beauty had to go. 

CALL IN THE PLANT CORONER: WHEN DISEASE WINS

I would be crazy to complain about anything that happened in the garden this summer. The weather has been lovely, possibly even perfect. For the most part we had warm temperatures with plenty of rain mixed in. Sure, there were a few dry weeks, but I only had to do supplemental watering a handful of times.

And yet, there is one problem in my happy little garden. And it's a big one: verticillium wilt. It's caused by a nasty little soilborne fungus that attacks a large variety of plant species.

The 'Lemony Lace' elderberry looking fabulous in early summer. And it looked great until just a few weeks ago.

Here's how it presented itself in my yard. Two weeks ago my sister-in-law and I were walking the garden, taking special note of my 'Lemony Lace' elderberry, a lovely cutleaf shrub with bright green foliage that looks like a Japanese maple. Four or five days later, I was enjoying cocktails on the patio when I noticed from afar that the elderberry looked a little odd. Upon further inspection, I noticed that half of it was wilted. My first instinct was to give it some water. This, of course, made no sense. We'd had a good amount of rain and it was an established plant. And only part of it was wilted. It occurred to me that this may be verticillium wilt, which I'd heard of but never seen, and when I did a little research it was clear to me that's what it was.

Two weeks ago I noticed that about half of the branches were wilted.

About a week later, the wilted branches were brown and the leaves had fallen off.

I meant to get out quickly to deal with it but I needed bleach to sterilize my pruning shears and another week passed before I could get out there. When I did, I found that the branches that had wilted were completely devoid of leaves, all of which has dried up and fallen to the ground. I don't usually get too crazy about sterilizing my pruners, but verticillium wilt is particularly nasty and I didn't want to take any chances.

I'm not usually the most careful gardener about sterilizing my pruners, but I took no chances of spreading verticillium wilt. This was about a 10% bleach solution and I dipped the pruners in it between every cut.

I cut away the wilted branches, but honestly, I'm being exceptionally optimistic. If the rest of the branches (which look a little silly now) make it through the fall, the odds are the elderberry will come back next year, look good until late July or August, and then the same thing will happen. And the more it happens, the more I risk having the fungus that causes it spread, putting other plants in danger. Elderberries are susceptible to it, but so are viburnums, which my yard has plenty of and I would hate to lose any of them. In fact the list of plants that can succumb to verticillium wilt is long.

This all had to go. You can see that the leaves of the non-wilted branches are yellowing a bit, which is probably a sign that they will succumb to wilt soon.

Since the fungus that causes verticillium wilt lives in the soil, the only way to get rid of it is to either remove the plant and the soil around it or to solarize the soil by digging it, wetting it down and pinning clear plastic over it to "cook" during a hot time of the year for several weeks or even months.

All of which is a real drag. I loved that elderberry and it was a real star in the garden, but it will have to go. When I remove the soil, I'll plant something that is resistant to verticillium wilt in its place and to be extra safe, I will dispose of the soil in some way that I don't have to worry about it spreading. This may be in the garbage or possibly I'll throw it in the fire when we have a bonfire.

One last note: Waiting until all the leaves fell off was a really bad plan. I had to scour the area for all those leaves, making sure to remove all traces of them. All of the branches that I cut off went directly into the garbage. I could have burned them but it could be awhile before we have a fire and I didn't want them sitting around the yard.

I'm sad about the whole thing, but the sooner and more thoroughly I take care of it, the less likely it is to spread to other plants.