Garden writer and MBG Executive Director Bill Finch is happy to answer your gardening questions.
Email them to plaingardening@yahoo.com

GLORIOUS GULF GARLIC

Lorz italian

What a great discovery it was, figuring out that we can grow really great garlic in Mobile – I mean, really exceptional garlic, garlic that will set your world on fire.

But to grow great garlic in the Deep South, you need to know two things: First, you MUST plant your garlic in fall or early winter. Second: you want to choose garlic varieties adapted to our climate.

A lot of the garlic written about in gardening magazines is designed to grow well in really cold climates. As a result, it requires long, cold winters before it starts developing taste and begins bulbing properly. So rather than trying to grow the fashionable rocambole garlic from Northern Europe, Southern gardeners will be wise to look to garlic varieties from latitudes and climates that are similar to our own, garlic varieties that develop best in milder, wetter winters.

And because excess rainfall at harvest time can cause all kind of issues with garlic, it’s also good to get varieties that are harvestable well before the summer rains and humidity set in.

Where in the world might you find such garlic? Exactly where we find so many of the plants that perform well in our climate – from Japan, southern China and southeast Asia. These areas have climates similar to our own, and garlic varieties from Thailand and Southern China have, year after year, performed extraordinarily well in Mobile gardens.

When grown in our climate, these garlics can be extraordinarily productive and distinctively tasty. Whether you eat it raw or cooked, you’ll immediately recognize how different (and better!) it is than store-bought garlic.

Most of these varieties are part of an unusual family of garlics called turbans. Turbans seem to have an affinity for warm, wet climates. They are also unusually robust, producing abundant foliage and a hefty bulb. And because they are designed to grow all winter, they are among the earliest of all garlics, ready to harvest in the latter part of April or early May along the Gulf Coast, before excess moisture and soil diseases become a serious issue.

This means they fit our climate like a glove. And it means you can have fresh garlic from the garden virtually all year long. I harvest the leaves for cooking in fall, winter and spring, and then have plenty of bulbs from April through October.

Turban varieties I’ve had the best success with

Lotus

• Blossom — A south China variety with a “blossoming” raw heat; year in and year out one of the most productive.
• Lotus — South China. Hot raw, tingly even when baked. Matches Blossom for productivity.
• Chinese Purple — Good flavor and color. Said to store a little longer than other turbans.
• Thai Fire — Intense raw, tingly cooked. The Thai varieties seem to never fail.
• Thai Purple — Very reliable, with a raw tingle.

Artichoke varieties are somewhat less dependable than turbans during mild winters. But they have some fine qualities and flavors, and a few will “keep” longer than turbans, which means you can still be cooking with the spring harvest of bulbs as late as November and December.

Three varieties that have performed well for us:

Inchelium red

• Inchelium Red — An old West Coast variety that always produces bulbs with good flavor. Bulbs size can be disappointing, and in wet conditions, they are prone to re-sprouting in the ground.
• Lortz Italian — A really delicious garlic, unusually intense for an artichoke, that keeps a very long time. Some had poor performance during this past very mild winter, but abundant harvests during our colder winters.
• Thermadrone — An old French variety, with a straightforward garlic taste, maybe a little buttery. A fairly consistent performer.

If you want these garlics, chances are you’re going to find them only two places:

1. Order from Filaree Garlic Farm, www.filareefarm.com. There are other places that sell a bit of garlic here or there, but no other source has so many garlic varieties, and most important of all, no other source has so many varieties adapted to Gulf Coast growing conditions. Because we’ve introduced so many Gulf Coast gardeners to garlic, Filaree often sells out of many varieties early in the summer. If they do, you’ll have one more opportunity (see no. 2).
2. The Mobile Botanical Gardens Fall Plant Sale. We’ll be selling potted and bagged trial-sized selections of Filaree Farm garlic at the plant sale in mid-October, which is a great time for planting. If you’re a member, we’ll be taking orders on our online catalog in September.

Sign up for our next session of Gulf Coast Gardening, or the popular Fall Vegetable Gardening for more Fall planting advice to use in your Gulf Coast Garden.

____________________________________________________ 6/21/12

THE TOMATO HEARTBREAK DISEASE,
AND HOW TO DEAL WITH IT

They call it bacterial wilt, but you know it as the heartbreak disease.

It’s a killer for any of us who love tomatoes, because it seems to focus almost all of its damage on tomatoes, and always strikes when your tomatoes are at their peak, when your tomatoes are the picture of tomato health, so full of tomatoes that you’ve got sugar plum fairies dancing around in your head.

The next day, the leaves are flagging for no apparent reason, and you water and scratch your head. Two days later, the plant is dead. Boom. Almost overnight. And you get this horrible feeling in the pit of your stomach like your girlfriend just ran off with the mailman.

Bacterial wilt: later stages.

That, simply, is how you know you’ve got bacterial wilt. Nothing else will wreck your tomatoes in such a distinctive and immediate way. No other tomato disease will leave you feeling so hollow and useless inside.

And of course, what can you do once you’ve got it? Even if there were such a thing as emergency rooms and intensive care units for plants (there are none, I’ll remind you), what good would it do? Because by the time you recognize your plants are suffering from bacterial wilt, the disease has already progressed to the point that the entire plant is just hours away from total collapse.Let me wring your broken heart one more time by letting you know that bacterial wilt is distressingly common along the Gulf Coast. I don’t know of any gardener who grows tomatoes frequently who hasn’t suffered from it. Shoot, we lost some of our tomatoes at Mobile Botanical Gardens to the disease. And some gardeners have been hit by it so many years in a row, they’ve simply abandoned growing tomatoes in their yards.

But wait. There’s no need for you to abandon tomato growing. If you understand the conditions that promote the development of the disease, you may be able to avoid it entirely.

The bacteria that promote bacterial wilt are likely already in your soil. But they don’t seem to proliferate and bother your tomatoes except when the soils are sopping wet with moisture for long periods, and when the roots of your plant have been repeatedly stabbed and chewed on by the minute soil creatures known as nematodes. These nematodes leave holes in the roots that give easy access to bacteria.

I’ve been able to avoid bacterial wilt almost entirely in my home garden by creating a fresh, 6-inch layer of topsoil each year in the areas where I grow my tomatoes. This layer of new “SuperSoil” — created, very simply, when a pile of leaves broke down into topsoil over the winter — provides excellent drainage that discourages the kind of wet soils that bacterial wilt thrives in. This fresh layer of soil is also relatively free of the wilt bacteria. And because nematodes travel into new soil very slowly and don’t do well in soils high in organic matter, there’s very little nematode damage to the roots of my tomatoes, and thus very few entry points for the bacteria.

I supplement this technique by rotating the tomatoes to a new part of the garden each year. Creating a fresh layer of topsoil may be almost as good as rotating, but with a disease like bacterial wilt, you may not want to take any chances.

You can try some of the new bacterial-wilt resistant tomato varieties, like the Hawaiian tomato called Kewalo. There aren’t many of these varieties, I should warn you, and some have complained about a lack of taste.

And finally, you can, as some gardeners do, resort to growing your tomatoes in containers in sterilized commercial soils. You’ll certainly avoid bacterial wilt that way, but you may encounter a few other difficulties along the way.

_______________________________________________

Please, Don’t Take My Basil!

The disease:Basil downy mildew

What it affects: Only basil is affected, and mostly the popular large-leafed sweet or “Genovese” basils. Many other basil types may be resistant.

Symptoms: Leaves appear yellow, as if sunburned, except that the yellow pattern often doesn’t cross the leaf veins, creating a blocky pattern. Affected leaves eventually develop a blackish fuzzy shadow on their undersides, then turn brown or fall off completely.

Prognosis: Plants may slowly recover IF temperatures remain high enough for a sufficient period.

Treatment: There is no cure for the disease once it has affected the plant (other than controlling moisture and temperature).

Avoidance: Use basil varieties, such as small leafed Fino Verde, or Thai basil or lemon basil, that are resistant to the disease. Plant large-leaf sweet basils late in May or June, after nights have begun to warm. Use non-infected seed. Don’t use overhead watering.

Look, maybe I could live without impatiens, but can I really survive the summer without basil, that deliciously dependable vegetable that has become the mainstay of Gulf gardens?

I had to ponder that horrible possibility last week when I discovered that my basil had been infected with basil downy mildew, which may turn out to be the first case officially documented in Mobile County.

But clearly, I’m not the only gardener in Mobile having trouble with basil this year, so it’s pretty apparent this disease is already widespread here, and is here to stay. What’s that going to mean for one of our favorite summer vegetables? It’s not entirely clear yet, but it will almost certainly alter the varieties of basil we grow, or the times of planting, or both.

The invasion of basil downy mildew has virtually wiped out sweet basil crops in many parts of the U.S. for the past several years. But — as was the case with the impatiens downy mildew we looked at last week — there was some hope that the basil downy mildew would not be as widespread on the Gulf Coast, where higher temperatures tend to put a damper on cool-climate downy mildews.

That was a false hope. This year, basil downy mildew threatened to wipe out my spring crop of basil. Since I hadn’t seen it before, I was a little confused by the symptoms. The leaves looked yellow and slightly cooked, as if they had been sunburned. At first, I tried to figure out why they might have been sunburned. Then some of the leaves started looking brown and crispy on the edges, and some plants lost nearly all their leaves. It quickly became apparent I wasn’t dealing with simple sunburn.

There were two clues that identified the problem as a mildew-like disease. The yellowing on the leaves looked kind of blocky in places, as if the veins in the leaves had stopped it from spreading evenly. That kind of blockiness is a good sign that a fungal disease is the culprit. So I looked under the leaves, and sure enough, they were covered with a tiny mat of black fuzz. You had to look carefully to see it, but it sort of looked like the bottom of the leaf hadn’t shaved in a day or two, and suffered from a morning shadow. That minute black fuzz was the “flowering” of the downy mildew that had infected the leaf. It was producing microscopic mushrooms that were spreading their spores all over the garden.

John Olive, the Auburn University horticultural disease specialist, came by this week to offer the official pronouncement. But there’s not much doubt that we’ve got it. And so do a lot of other gardeners. I’ve been hearing from gardeners all over Mobile who say that their basil leaves turned a funny yellowish color this year, as if they had been sunburned.

Yep. They got it, too.
Is it the end of our budding love affair with basil?

No, thank goodness. And we here on the Gulf Coast may actually have some advantages in dodging this disease. The disease is more heat tolerant that most downy mildews, but it does seem to develop best when night temperatures are fairly cool (below 70 degrees) for long periods. That means it can continue to spread and develop in areas like Wisconsin and Michigan and Asheville, North Carolina, because even in the height of summer, night temperatures consistently fall below 70 degrees.

But as the summer has heated up here along the coast, much of my basil has recovered, or is not showing symptoms. And newly planted basil does not seem to show any signs of the disease. We may be able to credit both the hot and dry days and the very warm nights. This time of year, temperatures rarely fall to a level that allows the downy mildew to thrive. At least that’s my reasonable estimation, based on what we know about this disease so far.

On the other hand, basil grown in spring and fall should continue to be quite susceptible to the disease. One way around that problem is to grow basil varieties that are not susceptible to downy mildew. So next year, instead of planting the usual large-leafed “Genovese” and sweet-leaf basil, I’m going to be planting small-leafed basil varieties, such as Fino verde basil, which actually has a more refined and sweeter taste than Genovese (though it’s a little less productive). The distinctive tasting Thai basils, the lemon basils and cinnamon basils, and the compact spicy globe basils also appear to be highly resistant to the disease, though they sometimes don’t substitute for the more familiar sweet basil.

More information about basil downy mildew is available from Cornell Universtiy’s College of Agriculture and Life Sciences.

impatiens walleriana

GOOD-BYE IMPATIENS?

If you love impatiens, or if they’re the foundation of your summer garden color, let me be frank: The news ain’t good.

Impatiens all over town look like they’ve been gnawed to a nub. The foliage is gone. It’s only affecting the most common impatiens varieties — the “SunPatiens” and the New Guinea impatiens seem immune. But the old favorite walleriana impatiens varieties, the ones that come in so many colors and that are so widely grown — they’ve been hammered.

impatiens walleriana with downy mildew

It’s a new disease, one that hasn’t been seen in the Gulf Coast landscape before. It’s a kind of downy mildew that affects only impatiens, and in the landscape, there’s no treating it once the plants are infected. In Europe, it’s now so widespread and uncontrollable, gardens there have essentially abandoned growing standard impatiens all together.

In spite of the problems in Europe, plant disease experts in the South were originally optimistic. At worst, some disease experts figured, the disease would only attack impatiens in greenhouses or those put out very early in the year, in February, March or April. There was reason for that optimism: Most downy mildews develop well only in cool damp conditions — or at least in conditions that seem to us to be cool, in the 50s and 60s. But as Auburn University disease expert John Olive points out, this downy mildew seems to be very tolerant of relatively warm temperatures, in the lower 70s at least. So the disease is clearly active well into the beginning of our warm summer period.

disease resistant sunpatiens

Is there any way to protect your impatiens? Probably the only certain way to do that is to plant the impatiens species and cultivars that aren’t susceptible, like the new SunPatiens varieties, the ones with the long, narrow, dark-green leaves. New Guinea impatiens are also immune but they have other problems.

If you’re growing standard impatiens, the Impatiens wallerianavarieties with the familiar rounded leaves about the size of a quarter, you might be able to delay this disease by avoiding the white impatiens cultivars and by avoiding overhead watering, which creates the kind of constantly moist conditions that mildews thrive in. But with our humidity and frequent rainfall, the disease will likely catch up with you at some point.

Surely there’s some cure for this disease? John Olive says no. As is the case with most fungal diseases, once it’s obvious on the plant, it’s too late to use a fungicide. Olive said some fungicides can be effective at delaying the onset of the disease, but only if they are used BEFORE the disease develops and are applied constantly, and in some cases every few days. He adds that those fungicides are simply not practical or effective in the landscape or in home gardens.

There is some chance that impatiens not completely defoliated may recover as the night temperatures warm in the middle of our Gulf summer. Even the most heat tolerant downy mildews can’t survive if temperatures never drop below the upper 70s (which is often the case in the middle of July). Higher daytime temperatures, in the upper 80s and lower 90s, may also suppress or eliminate the disease. But from a practical standpoint, it doesn’t make sense for growers to continue growing and selling these varieties if they’re not going to survive normal spring and fall temperatures, so we may well be seeing the last generation of old-fashioned walleriana impatiens on the Gulf Coast.

And a quick reminder: The disease ONLY affects impatiens and their close relatives. So you don’t need to worry about the disease “jumping” to other plants.

Stay tuned next week, and we’ll tell you about ANOTHER downy mildew disease affecting only basil plants. It’s a bad situation, but there is still room for optimism, and we’ll tell basil lovers what they can do to escape the ravages of this new disease.

(Special thanks to Auburn University disease specialist John Olive for providing information for this article.)