Adrian Higgins on summer gardening

Courtesy Ball Horticultural Co.
Jul 09, 2015

Washington Post gardening columnist Adrian Higgins took questions on gardening.

Can you please recommend an effective deer repellent? Yesterday, I returned from vacation to find my petunias and impatiens eaten in the containers. All the flowers are gone and some stems remain. There is a family of deer that frequent my area daily.

Hello all. If it were any clammier in Washington today we'd need gills. This steamy weather is tough on gardeners and tough on plants. Let me know what tips you might have for coping when it's so tropical. Repellents can be effective, and it's always better to apply them right after planting rather than after the deer have found your flowers. There are a number of brands and you will probably find a greater selection at garden centers and feed stores than the big boxes. The liquid comes either ready to use or, if you have a large property, as a concentrate that is diluted into a sprayer. They contain stickers which allow the repellent to linger after rain, but given the amount of rain we have had in the past six weeks, I would apply it on a regular basis. 

The cover of this week's Local Living features Adrian on the best kind of fronds with benefits--ferns. Here is a link.

This summer, like most summers, I have some vigorous squash and bell pepper plants growing as volunteers in my compost pile. But when I buy plants from a garden center (tomatoes and cucumbers) they barely thrive. The store-bought plants are planted right next to the compost pile, with a lot of aged compost worked into the soil. The area gets sunlight from morning to mid-afternoon. I feel like a cursed gardener.

Your seedlings seem to be saying, the more compost the better. Your transplants are inevitably shocked when planted and this has a stalling effect. It's either too cold, too hot, too sunny, too windy, too dry or too wet. One aspect of planting is vital but often overlooked, that is the working of the rootball. The roots should be teased out, gently, patiently, with your hands in a way that minimizes damage but gets the roots out of their pot mentality. I would directly sow cucumbers. 

Hi Adrian, Last year was the first year we had a vegetable garden in our yard. Although it did pretty well, I had a nasty problem with anthracnose on tomatoes. I mulch, prune bottom branches, and have a drip irrigation system. I rotated tomatoes and related plants to a different bed this year, but was dismayed to see the problem cropping up again this week. What can I do?? I know it's been very wet these last couple weeks, but in all my years of community gardening I never had this issue. Early blight, yes, but never anthracnose. I'm preplexed as to where it's coming from.

This is the overwhelming dynamic so far this summer -- an enormous amount of precipitation that is causing widespread stress and setback in the vegetable garden in particular. Normal cultural steps that you outline help but may not be enough given the amount of water. If you are sure the problem is anthracnose I would take out the tomatoes and plant something else outside the nightshade family. . 

Do you have any suggestions for books, apps, or software that help with landscaping design? I'm trying to create a garden that's a mixture of edible plants and native Maryland perennials, which will flower through as much of the year as possible. I have lists of Md natives (with info on amount of sun needed, type of soil preferred, etc.), but I'm just not sure where to start with the planning!

This is such an encompassing subject that there are few if any books etc. that can address this, even if they purport to. Before you even consider plantings, you must consider topography, drainage, soil conditions, light conditions, etc. Half of landscape design (or more) is about fixing problems. Also, each site is different. The basic advice I would give is that you must first build a physical framework for the garden before you can address the vegetation. A writer and designer named Gordon Hayward does a good job of deconstructing these processes for homeowners, and I would commend any of his books. 

I moved into my house about a year ago, and am now starting to think about long-term landscaping design. However, presumably for house-selling purposes, the prior owner planted shrubs all around the house, most of which are either ill-suited for their location or that I don't like. I've already removed several that were on their last legs, but what about those that I don't like but are in good shape? Is there somewhere to donate unwanted plants?!

Not all shrubs are created equal. If someone offered me a privet, I think I'd pass, for example. Also, some shrubs can be moved quite easily, such as azaleas and boxwood, but others are a devil to move, because of their root system. The best time to move a shrub is in September and October, when traumatized roots have a chance to repair themselves before the winter. Moving a large shrub any distance usually requires it to be balled and burlapped, this is not a quick job, and may require more than one person. You may ask neighbors if they want any of your surplus. 

Okay I ripped out the sad sorry yellow tomato plants (note to self don't try San Marzano seeds again.) so what veggie to plant to sneak in a consolation prize before winter sets in?

I am replacing sodden tomatoes and peppers with fresh sowings of cucumbers and beans, it's a bit late but worth a go. You could also try carrots. It's a little early to be sowing lettuce and other salad greens, I would do that in mid August but I know gardeners who are sowing lettuce now and plan to take them at baby stage. 

I've been using the "Liquid Fence" brand now for the third summer with great success, which works for rabbits too. After having our many hostas mowed down a few years ago, the deer don't touch anything once it has been sprayed. I usually apply once in the spring when new growth is coming out to prevent them from eating the new shoots/growth, then once again about a month later after leaves have fully emerged. I find that second application lasts a good two or three months - practically most of the summer - but as Adrian said, with lots of rain like this it might need to be done a little sooner. A little goes a long way - you don't have to completely soak your plants with it - just a nice misting of fine spray. As an FYI - a lot of damage I used to blame on deer in our yard I've learned is actually being done by rabbits, and squirrels (esp. stripping of young tree bark).

Thanks for adding this. 

tell it from early and/or late blight, I mean.

Anthracnose is generally seen as lesions on the fruit, whereas early blight is the common yellowing of leaves, especially the lower ones. 

My container plantings of cherry tomatoes have grown up nicely and have lots of small green fruit, but the bottom leaves are yellowing and withering, eventually falling off. Could it be all the rain we're having? My internet searches find people saying it's due to lack of water, but it's rained almost every day here in DC since May!

Normally, a problem with container plantings in summer is that the soil dries out and gets awfully hot. The more likely problem this summer is that the soil is waterlogged. Containers must drain freely and with the amount of rain we have had, even free draining pots that sit directly on a hard patio can stay wet. You can set your container on bricks or buy little feet that will elevate it. Clean up the diseased leaves and hope for the best. 

Our zucchini plants started out so promisingly this summer but they seemed to get waterlogged. The base of the plants almost looked moldy, the stems/leaves turned yellow and the actual zucchini started disintegrating at the ends. I finally gave up last weekend and pulled them all out. What was it that killed my zucchini? Also, is there anything I can plant that may bear fruit/veggie this summer? I have a very sad bald patch in my garden now, I'm hoping that my tomatoes will hang in there. Thanks!

See my earlier post on sowing afresh. Cucurbits are thirsty and hungry things but also cannot abide waterlogged soil. It might be worth directly sowing small fruited winter squash such as acorn or butternut. Try and fine an early season variety that will mature in 75 days or so.  

I planted it at the back of a bed that backs onto a white-painted concrete garage that gets full sun all day. It's shaded out the meadow rue next to it and is starting to shade out the rosemary. Should I cut it back or move it? The bees & butterflies love it.

Yes, even though it may be in flower, I would cut it back by about half and expect a later reflowering. Another consequence of the moisture is that many perennials are flopping and could do with cutting back.   

I love Rosalind Creasy's book 'Edible Landscaping' - and it looks like she has a website now!

That's full of rich images, from which to gain inspiration. I had the pleasure or writing about Roz a while back and seeing her garden in the Bay Area. Ironic that California gardeners are craving moisture and we're trying to cope with far too much of it.   

Did your favas produce much? Mine had a poor crop and I recently pulled them as they were looking bad in the heat

They were robust but about as fruitful as a strawberry in the desert. I got four beans, but, they were delicious! I ate them raw from the garden. Once temperatures exceed about 85 degrees, the flowers don't produce. The whole row is being pulled this weekend.  

Our crape myrtle has a branch that hangs over our front walkway, so anyone walking by has to dodge it. Someday the branch will be tall enough that it won't do that. But in the meantime, do we cut it back or live with it?

I don't think your branch is going to get much higher, even as the tree does. You may selectively prune some twigs while keeping its natural look, this may take some of the weight off it and it will elevate. Otherwise, I would remove the branch entirely in the correct manner.

Does that mean to cut half the stems down to the ground, or to cut off the whole upper half of the plant? Thank you!

I meant cut back each stem to about a half of its length. It will look stubby but should soon refoliate. 

Is there a certain time of day that is best to pick my blueberries, raspberries or grape tomatoes that will ensure they are at their sweetest?

The best time to harvest fruit as well as herbs is early in the day when the sugars and oils are more potent. 

There is white lacey "stuff" on my parsley plant stems. Is this a type of fungus?

Parsley likes cool weather. To have any at the moment is pushing your luck, I'd say. You may be seeing mildew. In any case, I think I'd pull it and start again in early September. Or sow seeds in August to get a jump on the fall.  

Our lilac bush is huge but has not been flowering much. I know we need to cut it back, but can we cut it all at once? I had heard we need to do it in thirds. Any advice?

The idea is that you rejuvenate the shrub over three years (removing a third per annum). If you want to keep it, I would take out the oldest stems, and allow just some of the suckers to grow and mature. I feel that big old lilacs just aren't for this climate, they take up too much garden space and bloom at a time when sudden heatwaves can limit flowering to a week or so. The rest of the season, you are looking at a dull, heavy shrub that will proceed to get powdery mildew. Some of the smaller cultivars have more value, in my view. 

The text for the Ghost fern (Athyrium × ‘Ghost’) gives its source as the garden of a Nancy Sweet. Surely you meant Nancy Swell. Nancy Swell was one of the regulars at the May Green Spring events in the old days. She and her husband had a small stall where she offered an intriguing variety of plants barely if at all in commerce. My first Danaë racemosa, , Adiantum × mairisii, various Asarum, various Trillium and many others came from her garden. This was back in the days before Asiatica and Plant Delights brought so many of these plants to a broader public. She took her motto from Shakespeare: “We have the recipe of the fern seed, we walk invisible”. Ferns, of course, do not have seeds, and in spite of what I read in the newspaper this morning, they do not produce seedlings.

We'll look at that and correct it if needed. Thank you.  

I need to put my blueberry bush in a larger pot. I assume now isn't a good time to do that since it's fruiting. So when is a good time to do that?

Yes, wait until you have harvested the fruit, find a slightly larger container, and repot in September. Alas, we have run out of time. My next column (or two, perhaps) will deal with problems associated with all this rain. Stay cool out there. 

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Adrian Higgins
Adrian Higgins is The Washington Post's gardening columnist. Read his latest columns and stories here and follow him on Twitter.
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