Adrian Higgins gave advice on tending your garden in the summer

Jul 24, 2014

Washington Post gardening columnist Adrian Higgins took questions on how to improve your garden in the summer.

I had planted two heirloom varieities of tomoato obtained from a farmer's market vendor, they seemed to really start to struggle in the first brief heat wave and now most of the nine are mostly dead. Looks like wilt, various parts of the plants turned yellow then shriveled up and turned dead brown. Am I crazy to think I could attempt again next year with better varieties (I've had other types do better than this!) and being more generous with the water via drip lines from day one? I used to think the guys needed 1 inch per week but do they perhaps need more in our climate as long as they aren't sitting in wet?

Greetings all. I'm a fan of heirlooms and their stories but many simply don't have the inbuilt disease resistance of modern hybrids. Yours may have suffered from late blight, which is a killer. Most tomatoes around here suffer from a less pernicious disease called early blight, which causes the lower leaves to yellow. Good sanitation is essential with early blight, however. You should remove the leaves from the bed entirely (throw them away, don't compost them). I spent an hour last weekend cleaning up my tomato plants. Both they and the gardener felt much better afterward. Late blight causes blackening of leaves and stems and collapse of the plants. The rule of thumb for any morose veggie plant is to pull it, clean up the leaves, and evaluate whether the site or the cultivation contributed to the malaise, and alter things for next year. 

My giant dill has gone to seed and will soon be ready to harvest. Last year I saved the seeds in a paper bag to fully dry, but when I opened the bag, I realized that some of the “seeds” were moving – bugs! How do I avoid bugs this year? Should I just leave the seeds out on a paper towel until I’m sure they’re dry and bug free? Is a glass container the best way to store the dill seed in the kitchen?

If seeds are fully ripened and allowed to dry before storage -- spread them on paper in an air conditioned room for a week or so -- they can be stored in the freezer. This will kill most bugs and their eggs, but not the seeds. Give it a go. 

I live inside the beltway in Virginia and I'm hoping to plant some vegetables for the fall growing season for the first time. I do most of my gardening in large pots and buckets due to limited space and lots of clay. My yard averages 3-5 hours of sunlight per day. I was hoping to plant beets, spinach, carrots and maybe peas. Are these good choices? Any other suggestions? (I'm also considering putting in a small cold frame.)

Don't bother with the peas. Your conditions are a bit dark for most vegetables and herbs. You could try carrots, spinach and (you didn't mention) lettuces. Parsley will take partial shade as well.  

I have had a decent crop of green zucchini, but the leaves are starting to turn white and fewer zuchinnis are growing- is the plant dying- should I pull it and plant something new? if so- what would be a good replacement for this time of the season(sorry lettuce isn't in the running)

This sounds like powdery mildew, which will eventually weaken the plant to a point where it struggles to flower and fruit. Once it appears, it is nigh impossible to reverse and it is better to pull it. There must be other gardeners begging to unload their zucchini. You could plant bush beans in its stead, or sow kale for the fall -- that's what I'm doing this weekend. 

What's your feeling about glyphosate? I've always understood that it was one of the more benign herbicides, since it's supposed to evaporate quickly, and I don't know what else I can use to keep down the pokeweed that the birds sow so liberally in my 2/3 acre.

I prefer to hand pick or hoe weeds, but there are times when herbicide is the only option, and glyphosate seems to be one of the least toxic. I have a wormwood established in an embankment and I keep cutting it back and it keeps growing and I'm now on the verge of using glyphosate on a paint brush to target it without bothering plants around it. Old pokeweed develops huge tubers -- I think you need many repeated doses of glyphosate to kill the entire plant. I dig it out with a mattock. 

Wondering why our hydrangeas have produced no blooms this year. Just green leaves so far. Usually we have a profusion of blue and purple blooms, but not this year. However the oak leaf variety is doing well. Can you shed some light on this? Thanks!!! Laura in Silver Spring

This is down to the harsh winter, which killed the buds of flowering stems that developed last year. As long as you don't prune them harshly, they should bloom next year if the winter cooperates. 

Mr. Higgins, I am hoping you can advise me on why my purple coneflower is not blooming. It has vigorous, healthy foliage but no buds or flowers. I purchased it from a native plant supplier and planted it this spring. Does it need a year to adjust? Also, it doesn't quite get full sun; more like 4-5 hours a day. Is that insufficient? Black-eyed susans right next to it are blooming well. Thank you!

It may need another year to provide the oomph for good flowering, but it would prefer to be in a sunnier location. High nitrogen feeds (even scattered lawn fertilizer) will also reduce flowering.  If you can, I would find a sunnier spot for it. 

we've finally given up on our beloved Brandywines because we can't stay ahead of the blight. What do you recommend for that wonderful flavor?

I find that many of the heirloom oxheart types perform well and give you that beefsteaf size and flavor. Look for them in the catalogues this winter.  

Thanks for today's article on basil and the heat of late summer. I have a big patch of basil, thanks to leaving a bolting plant in the garden all winter, but it's getting hard to stay ahead of the bolting now. Should I harvest the whole thing and freeze the leaves in oil, and start over with new plants?

Yes, I would. You can put in new plants (some folks use the whole herbs available in supermarkets as a cheap source).  In this heat and with gentle daily watering, basil seeds will germinate in less than a week. 

I’m growing grape tomatoes in my garden, which I didn’t grow from seeds but bought as plants. However, about 25 feet away a singular grape tomato plant is growing from the crack between the stone paver and the wall of the house. Here in Brooklyn, we call plants or trees that do that “ghetto palms.” It’s not uncommon for weeds to do that, but how did my plant get there if my others hadn’t seeded yet and I never used tomato seeds in the first place?

Cherry tomatoes are prolific seeders and some of their seed survives the winter, this is why you see tomato seedlings erupt in May in garden beds, compost piles, etc. I tend not to keep them because I want to know the variety that I'm growing. Your volunteer may fruit. Good luck. 

I planted a large number of tulips and daffodils that looked lovely in the spring, but once their foliage died back, I was left with bare dirt. I don't want to plant annuals every year and am looking for something that either comes back or reseeds itself. Low maintenance and no more that 12-15" tall (flanks my front door). North side bed, gets partial sun. And hostas won't work as the deer decimate them. Any suggestions?

I would consider a late season perennial that can take partial shade. The obvious choice (other than hostas) is Japanese anemones. The toad lily might be another. 

I just cleaned out the planter box I had used for my spring peas(about 3 ft x 8in x 8in) and I'm trying to decide what to grow for a fall crop. I can move it inside to a window sill that gets full sun (noon-7pm) until the weather cools enough to move it back outside. What vegetable would you recommend? I'm intrigued by the lettuce and the scarlet beans you mentioned in your column but wonder if it's the right container for those.

I'm leery of trying to grow anything indoors that would prefer to be outdoors (or in a greenhouse). Certainly you could try some of the lettuce varieties that I write about today. Runner beans wouldn't be suited to a window box. I confined my piece today to lettuce, but there are many other greens that will grow merrily in the fall, such things as mesclun mixs, radicchios, spinach, kale, pak choi and other Asian greens. This is also the season for turnips. I'm serious!

My very overgrown button bush, when in bloom earlier this summer, had over 600 flowers and 200 bumblebees. Quite the sight!

This is a lovely indigenous shrub that does its thing when little else is flowering and, as you note, a magnet for pollinators. It really likes a moist setting and would be good to include in a wet area of the garden, along with Sparkleberry and myrica.  (If you have the room).

Good Afternoon! I am perplexed by the plant aralia "Sun King" and I would appreciate any thoughts you have. I have seen it listed as growing anywhere from 3 feet high to 6 feet high and those 3 feet make a difference in placement. I wondered if you (or any readers) had any experience with this plant in the mid-atlantic region. I've seen it likes moist soil and the site I'm considering is slightly dry with morning sun. I'm hoping that might make it more in the 3 foot range.

Aralias have their fans, I'm not particularly drawn to them -- they're rather coarse in winter outline. I don't know this cultivar, but aralias can grow to eight to 10 feet or more. You may want another shrub in that spot, perhaps a daphne or a clethra. 

I've got a dozen Romanasco Broccoli plants that are growing like gangbusters, but it's just leaves. Is it ever going to produce a head? Or am I just expecting too much too soon?

They should head but they are happier in more temperate climes. The key is to provide sufficient moisture to forestall bolting. You might have better luck putting them in the garden in early August for a fall crop. 

I had two fall-blooming camelias that were healthy for a few years, then developed a fungus that I could control pretty well with Fungo-nil, but this last winter killed them both. Now my spring blooming camelia is full of fungus, not responding well to the Fungo-nil, and I'm about to pull it. I don't want any more azaleas, but need something attractive and flowering that would be good against the house in part shade.

Any plant that needs fungicide on a regular basis should be replaced, in my view. I think you have a microclimate there of stagnant air. Consider newer varieties of hydrangea bred for mildew resistance, or perhaps a pieris. 

Hi Adrian, I'm in southern New England and am growing tomatoes in containers. The Sweet 100s are doing what Sweet 100s do, and are producing lots of fruit. The Brandywine, on the other hand, has produced flowers but only one tomato so far. Flowers appeared but dried up and fell off. I have heard this might be blossom drop, due to extreme weather, but the weather here was beautiful during the flower/pollination season: 70s to low 80s during the day; mid 50s to low 60s at night. Is there anything I can try? Or since I am growing an heirloom variety, do I just need to adjust my expectations? Thanks for any help.

This is the problem with Brandywine. Scant flowering and a long season of ripening. One thing is not to prune these old plants, let them sprawl and vegetate so that they put sugars into fruit development. You should also give them a tomato feed and some calcium to forestall blossom end rot. Tomato blossoms tend to abort at temperatures above 90 degrees -- you should be all right up there. 

just a vent but i think you'll feel my pain. i have lived in my house for nearly 30 yrs & the people who lived in it before me loved to landscape w/ pea gravel. since pea gravel doesn't decay, 30 yrs later, one of my flowerbeds is still gravelly. i pick through the dirt when i'm in the mood but mostly i grumble about gravel. anyway to get rid of it easily other than pick at it, like i've been doing?

I love pea gravel in the soil, especially our dense, clay soil. Your plants will like it too. It opens up the soil and brings in air and drainage. You would be amazed what likes to grow in gravel soil. You can add organic matter to improve the soil biology. One way to remove gravel from beds is to build a screened frame that fits over your wheelbarrow, and then shovel the soil mix on to the frame and wash the soil out of the gravel. It's messy and laborious and really not necessary. 

The polar vortex killed most of the garlic I planted last fall and I harvested the lone survivor once it started to flag. I have a planting bed without any bulbs in it. I wonder if it might be possible to start some garlic now so that it would grow to the point of being spring garlic before winter hits.

Garlic is best grown from cloves planted in October. The bulbs are harvested the following summer.  Garlic doesn't grow as well here as in less hot, humid places and I think it is important to give it a sunny, airy site that has been well amended and enriched. You must keep weeds at bay, including winter weeds. 

If anyone missed Adrian's Local Living cover story today, on the 5 annuals you should plant now to revive a hot summer garden, you can read it here.

Second year in a row we planted soybeans (edamame) and have gotten no flowers. These have done well in the past, and are fenced in so deer or rabbits are not the culprit. Have seen some evidence of flea (or other) beetles but not all that much. Any idea why these aren't producing?

They generally do OK here, I'm not sure the problem other than too shady, too nitrogenous a soil. It may be that it was wet when they bloomed and they didn't get pollinated, or your pollinators are absent. 

There's just one problem with raising turnips -- they grow to be turnips (ick!).

Ah. But fall grown turnips, eaten fresh, have none of the bitterness of the store bought article. Alas, our time has outpaced us. Thank you for all your questions. I'll see you here in about a month. Keep harvesting!

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Adrian Higgins
Adrian Higgins is The Washington Post's gardening columnist. Read his recent story on reinventing the winter-weary hydrangea and follow him on Twitter.
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