Maryland Grows

Blueberries and Micromesh

Long-time readers may remember that last year, after about fifteen years of successful blueberry harvests (meaning that the birds got no more than about twenty percent of the berries), I harvested absolutely none. Those I consulted who are in the know said that catbird populations were way up, and certainly they are fond of blueberries.

With the thought that all those well-fed birds likely had lots of babies, and would be back, I decided to take on the challenge of protecting a row of blueberry bushes that are part of my front yard landscaping, surrounded by other plants. I drove some rebar into the ground at intervals of several feet, put pieces of PVC pipe on top of them, and capped those with some pipe caps we had sitting around from a previous fencing project. Then when the flowering was done and the berries forming, I covered the whole thing with a big piece of Micromesh. (Link is to Gardener’s Edge, which is one place you can find this product. I have also bought it from Territorial Seed, but they don’t currently seem to have the 16’x16′ size I needed. I don’t mean to promote any particular product or company over others, so if anyone knows other sources, or other similar products, please leave a link in the comments.)

Micromesh has advantages over bird netting and floating row cover. It doesn’t tangle like bird netting, and it is tougher than row cover, unlikely to tear with reasonable use. Also, plants under it don’t heat up as they can even under lightweight floating row cover. The only disadvantage is that it makes an awkward and kinda ugly intrusion in the landscape:

But who really cares as long as you get blueberries, right? I’ll be able to take it off when the fruit is done, and maybe next year I can make it look a bit better. Here’s a closeup:

I’ve fastened the Micromesh to the pipes with the snap clamps you can buy for the purpose. And I have indeed been harvesting plenty of blueberries:

Two birds (both cardinals, a male and a female) found their way under the covering, and I had to let them out, but as far as I know those are all the incursions.

By the way, I also lost all my black raspberries last year (again for the first time), and meant to get the newly-organized planting netted this year, but didn’t get around to it. So I tied up a bunch of that shiny red-and-silver tape that is supposed to keep birds away because they think something’s on fire. Ha, no way. Birds are smarter than that. A friend says she is having good luck with one of those fake owls, so I may try that next. And come October I will look for some of the motion-activated Halloween decorations to bring out again in June. Mwa-ha-ha-ha-ha-ha.

By Erica Smith
Montgomery County Master Gardener

Brown Tips on Leland Cypress

seiridium canker
Q:  I have two beautiful, mature Leyland cypresses in my yard. I noticed that their tips are turning brown in spots. I see the same phenomenon on my neighbor’s evergreens that border my yard. Is this a disease? Do the trees need to be treated?

A: The brown tips on Leyland cypresses at this time of year are a symptom of Seiridium canker, a fungal disease. When these trees are stressed due to drought, poor planting techniques, and/or poor drainage, they can be susceptible to disease and insect issues. If the trees are planted too close together, there is a lot of root competition for moisture and nutrients, and the trees will also suffer from a lack of sunlight and poor air circulation.

There is no treatment for Seiridium canker. The brown tips will drop off naturally. Prune any dead branches during dry weather. The best recommendation is to keep the trees well-watered during dry periods. Keep mulch no thicker than several inches deep and away from the base of the trunk. Avoid over-fertilization. Leyland cypresses grow best in full sun with plenty of air circulation and appreciate moisture during dry periods.

Have a plant or pest question? University of Maryland Extension’s experts have answers! Send your questions and photos to Ask an Expert.

Cabbage harvest

Vegetable gardeners are of different minds about growing spring cabbage. There are those who love everything about this crop: the joy of watching seedlings that look like any other brassica gradually wrap their leaves around each other to form heads; the tidy appearance in the garden; the crisp crunch of cole slaw. And there are those who say it takes up too much space and is cheap to buy, so why would you bother?

I’d say if your garden is small, it’s not worth growing for those reasons. But if you have the space, give it a try! Unless you have a large family, though, or a lot of cabbage recipes to go through, make sure you don’t overdo the planting, and grow a few different varieties so you won’t be harvesting all at once.

When you’re selecting varieties, make sure you take a look at the “days to maturity” listed in the catalog or on the seed packet. This will let you know whether you’ll be harvesting your cabbage in a timely fashion (late May to mid-June) or whether you’ll be worrying that it might bolt in the summer heat before the heads form. Some cabbage varieties list days to maturity of as much as 90 days; these are meant for cooler climates than ours, or for fall harvest. In our Maryland heat, you don’t want to go above 70 days for spring cabbage, and the shorter the better.

Remember that the number listed for days to maturity is an estimate dependent on weather conditions, and that it refers to days from transplant, not from seeding. Cabbage will likely be growing indoors for one to two months before being transplanted outdoors. If you don’t have a seed-starting setup indoors, be prepared to buy your transplants.

Caraflex and Red Express cabbage, about a week from harvest

This year in the Derwood Demo Garden we are growing Caraflex, Red Express, and Katarina cabbages. Caraflex is a green cabbage that grows into a pointed shape; we transplanted it on April 4 and harvested some on May 30 – that’s 56 days, beating the stated 68 days to maturity by a lot. But most of it won’t be ready to harvest until next week. Red Express, a small-headed red cabbage, is supposed to mature at 62 days, and should hit that target just about right. I neglected to take a photo of Katarina, but it’s a new small green variety with a 45-day maturity estimate, and we harvested it this week at 42 days from transplant (it went in two weeks later than the others).

There are lots of other short-season varieties hitting the catalogs, so keep a look out for them. With erratic weather patterns increasing, short-season spring cabbages will be the way to go. Smaller heads (for smaller gardens and families) are also a new emphasis. All three varieties we grew are taking up less room than some old-fashioned cabbages, better for intensive planting. Although the outer leaves of Caraflex were about 18 inches wide and very impressive! Don’t forget that the outer leaves of cabbage are perfectly edible – just pretend they are collards.


By Erica Smith
Montgomery County Master Gardener

Protecting tomatoes against the cold

A picture worth at least a few words, which are: we are still expecting some cold nights coming up, so if you have tomatoes in the ground or are putting them in soon, give them some protection! I couldn’t wait any longer to get some of my huge plants in small pots into the ground, so I broke out all the protection devices I had lying around.

No endorsement implied (especially since I have limited to no experience with these devices), but from left to right:

Gro-Therm Perforated Transparent Film (over hoops)
Pop-Up Tomato Accelerator
Weather Defender Tomato Cages

Also in the photo: one tomato left uncovered to see how it does in comparison. Off camera: stuck two with my cabbages under a big row cover tunnel.

If you don’t have any of this stuff, you can still protect your plants. Just watch the weather forecast and throw an old sheet over the plants when temperatures dip below 50, especially if there’s wind. (Use rocks to hold it down. Also cheap.) Your plants will live without protection unless we actually get a frost, but their growth will be slowed and perhaps stunted.

Yes, indeed, I should have waited to start my tomatoes so I could hold them inside until well after Mother’s Day. My only excuse is that some of us MGs did a little grafting project (with which I had some success!) and had to get both rootstock and scions started pretty early since the grafted plants are set back in growth during recovery. And for whatever reason I decided that since I was using a 50-cell tray to start the plants, I needed to fill every cell… plus start some others a week later just in case… anyone need some tomato seedlings?

By Erica Smith,
Montgomery County Master Gardener

Upcoming GIEI open house by Montgomery County Master Gardeners

Please visit us on the afternoon of Saturday, April 29th! We will have all sorts of activities including: educational talks; workshops on plant propagation, mushroom growing, tomato grafting, and hydroponic gardening; children’s programs; plant and product sales; demos in our demo garden; and lots of Master Gardeners to answer your questions.

More information including a schedule here.

Claytonia, or miner’s lettuce

I’ve grown a lot of different vegetables at this point, but there’s always something new for me to try. Last fall I planted some Claytonia perfoliata, or miner’s lettuce, alongside spinach in my vegetable garden. Both of them have wintered over nicely and are being harvested now.

Claytonia is a odd-looking small edible green plant.

That specific epithet “perfoliata” refers to the way the leaf is pierced by the flower structure. Each of those leaves is about the size of a quarter, so you need a lot of them to make a meal, but you wouldn’t want to overdo it anyway because they contain oxalic acid which is toxic in large quantities. (More than you would want to consume; don’t worry.) You can use claytonia in a salad, or briefly braise or wilt it in a cooked dish. It has a nice lettuce-like, slightly sour flavor.

The plant is native to the western U.S., and gets its common name from the California Gold Rush miners who ate it for vitamin C, to avoid getting scurvy.

I’ve seen claytonia seed for sale in a number of seed catalogs. Try planting it this fall for a spring treat next year. Definitely a cool-weather plant, it will bolt in the slightest heat, so overwintering seems the best way to go. I didn’t give it any protection at all, but if you live in a particularly cold climate you could try it in a cold frame.

Four-season lettuce

One project we’re embarking on this year in the Derwood Demo Garden is growing lettuce year-round (or as close as we can get). Lettuce is a perfect crop for spring or fall: quick-growing, tolerant of cool weather, useful. But it often flags, turns bitter and bolts in hot weather, and heavy frosts will kill it.

The solutions to this are:

  • Grow in an area that gets more sun in the spring than in the summer – in the shade of a tree is great, or use shade cloth to alter the environment;
  • Choose varieties that suit the season;
  • Keep well-watered in hot weather;
  • Grow under a cold frame or plastic-covered tunnel in the winter.
Our salad tables are shaded by a large maple tree, so that’s where we will grow our summer lettuce. We’ve had success growing well into July before there, but haven’t systematically planned to keep going – it should work, though. We’ll try a few in the sunnier parts of the garden to see how they do, as well. And we’ll get the cold frame out for winter.
We’re starting our spring lettuces indoors for transplant.
Summer lettuces will be started directly in the salad table in part, plus we’ll start more seedlings indoors. We’ll use succession planting to start new plants every couple of weeks. If we are lucky with the weather and our varieties, we should be able to continue this through to fall, when more cold-tolerant lettuces will go in – some in the salad tables and some in the ground to be covered by a cold frame.
You can grow just about any lettuce for spring and fall. Some are particularly cold-tolerant and good for holding over winter. Here’s the list of varieties we’re trying for summer, all of which are supposed to be heat-tolerant and bolt-resistant.
  • Buttercrunch
  • Cherokee
  • Concept
  • Green Star
  • Muir
  • New Red Fire
  • Seafresh
  • Summer Bibb
  • Toretto
There are lots of other similar varieties out there, which we’ll try in subsequent years. This is a growing market niche, for obvious reasons – it’s hot out there, and we love our summer salads. We’re keeping track of which ones do best for us. If you have had success with summer-grown lettuce varieties, leave a comment – we’d love to hear from you.