Tough weather highlights summer's best performers

When tough weather lingers in summer, it can be discouraging. The plants look so worn! In addition, the simple advance of the  growing season means plants have filled out their space. The flower-to-leaf ratio drops. There's more green, less flower.

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If these conditions prevail in the garden and your mind today, take the most productive tack:

Focus on what looks good rather than the other way around.

That was our perspective as we decided what to do in our Detroit Zoo Adopt-A-Garden, one morning in July. Record setting heat and drought had taken their toll, and compounded the damage inflicted when a too-early spring coaxed plants to precocious growth that was then zapped by frost.

Yet when we were done in just two hours, 12 people had tweaked and watered 5,000 square feet so what had been a bit tired looking, was gorgeous. That's 400 square feet per person, a lot of ground to cover but do-able if you're smiling rather than glum.


Right: An arc of Weigela looking wonderful. These plants not only held up under tough conditions but had the gumption to rebound from their annual hard cut-back -- four weeks ago as their first bloom ended we cut all the four-foot tall blooming stems to the ground. So most of the foliage on these plants is brand new, grown out clean and full despite weeks without rain and days at a stretch with temperatures above 90 F. At the center of the line, giant coneflowers (Rudbeckia maxima) stand tall and unruffled. However, that's seems only right for a prairie native.


Right: This bed features winners from our last drought-time survey. Two years ago we dubbed them winners, divided and transplanted them here all in a day, even as that drought prevailed. They never faltered. In the foreground, flower stems from sea lavender (Limonium latifolium) beg clipping, and orange Helen's flower (Helenium autumnale) wants deadheading, too. But zebra iris (I. pallida 'Argenteo-variegata'), threadleaf bluestar (Amsonia hubrichtii) and peony look so fresh it takes the edge off. Also in this full sun bed, from our list below: Curly chives, northern sea oats, cooking sage and blue mist spirea.


Before introducing our stars... should know what conditions prevail that they rise above.

  • The garden has no irrigation system (we try to hand water annuals once per week).
  • The soil is excessively drained sandy loam and it's alkaline: Depending where you are in the 1/8 acre area, the pH is 7.4 to 7.8.
  • Sunlight:
    - Some beds are in full sun (plants there cast a sharp shadow for more than 6 hours per day),
    - Others are in part shade (between 4- and 6 hours' sun each day) and
    - A few beds are in shade (less than 4 hours' sun).
  • Some beds in sun are unfortunately populated with shade lovers. We've recently lost many trees to emerald ash borer and lingering construction damage, and haven't changed everything over, yet.

This year is the second worst I've ever seen, almost as bad as the devastating drought of 1988. A tree that looked great despite everything in '88 and is repeating that performance this year is Maackia amurensis (Amur maackia).

- Professor Emeritus Ed Hasselkus, University of Wisconsin, Madison -


Plants that sneer at heat and drought

Bearded irises (Iris germanica) have positively flourished in this weather.BuClemtsN6697s.jpg

Blue bush clematis (Clematis heracleifolia) is looking good. (Right.) We can depend on its small, light blue, fragrant flowers to make us smile in August. (You'll have to tune back in to see the flowers. What we care about today is its upstanding form and foliage!)

Blue mist spirea (Caryopteris x clandonensis, photo) is one tough cookie. Its blue flowers help cool the scene in late July. The heat may also have increased the fragrance of its sweetly scented foliage.

Bronze fennel (Foeniculum vulgare 'Purpureum') is straight, tall, smelling of licorice and abuzz with honey bees and beneficial insects.

Butterfly bush (Buddleia davidii) seems to say, "Bring it on, do your worst." Its flowers may be opening and finishing more quickly than usual as a result of the heat. Or maybe it's not the heat. Since so many other nectar sources have failed, pollinators are practically standing by for each bloom to open. Being pollinated immediately means each flower finishes more quickly.

Catmint (Nepeta x mussinii, photo) We take the lazy way after its first bloom and just cut it to the ground. Since we did that, there's been no rain and we never water this bed. Yet the plants are respectable clumps once again.

Celosia, an annual we have in greater number than usual because the rabbits leave them alone. So does the heat. (Note: We do water the annual flowers about once a week.)HypercmN6696s.jpg

Creeping St. Johnswort (Hypericum calycinum, right, foreground) It's been one of the surprise stars in our shady dry bed,  its presence there all the result of a whim, "What the heck, we have extra of this, let's see how it does in that space nothing else seems to like." This species is never loaded with flowers in our climate and sometimes bears only two or three, yet it's still worth having for its fresh greenery and dense semi-evergreen service as a groundcover.

Curly chives (Allium senescens glauca, photo) is a July blooming beauty. Its blue green foliage has a sinuous twist and is always immaculate.

Dwarf hybrid goldenrod (Solidago sphacelata 'Golden Fleece', photo). Stalks are developing now to hold its late summer bloom high above the leaves. Neither flower stems nor foliage look at all perturbed by the tough weather they've seen.

Fig tree (Ficus carica, photo) seems to think it's on holiday back home on a dry, hot Mediterranean hillside. (It's not hardy through our winters so we bury it each fall to keep it alive.)

Golden bleeding heart (Corydalis lutea, photo) The plants stopped blooming, which is a shame since they usually carry the shade garden through July. But otherwise the plants are their usual cheerful selves.

Grasses, especially some North American natives: switch grass (Panicum virgatum, photo) from the prairie and northern sea oats (Chasmanthium latifolium) from the Atlantic dunes.ChasmanN6706s.jpg

Ironweed (Vernonia glauca) is standing tall, soon to grace us with purple flowers and attendant butterflies.

Juniper. Such a shame that so many plant people shrug them off, "Oh, just a juniper."

Lambs ear (Stachys lanata, photo) looks wonderful, in large part because it was cut back on schedule. We did that two weeks ago, razing all its 18" flowering stems as it finished bloom.

Large flowered comfrey (Symphytum grandiflorum, photo) We often wonder why this plant isn't used more. Perhaps people confuse it with its tall, rank, seed-dropping cousin? Its pale yellow spring flowers are not show stoppers but talk about a sturdy, weed-stopping groundcover for sun or part shade!



Lavender (our Lavandula angustifolia variety is a long-stalked heirloom but we've forgotten its name!) This is another Mediterranean native loving the back-home weather. Photo.DianthBudlN6717s.jpg

Perilla (P. frutescens) A purple leaf, anise-scented, self sowing annual so prolific that some people list it as a weed. We thin the volunteer seedlings in spring, leaving some in strategic places to cover for fading bulbs or ephemeral perennials. Other than thinning, we do not fuss over them. They simply grow.

Pinks (Dianthus gratianopolitanus) has a reputation for being short lived but that's not been our experience. Some of our clumps of 'Bath's Pink' are 15 years old. Perhaps dry soil is conducive to long life for this species. At right, four performers: A) Dianthus, B) lavender, C) butterfly bush and D) horseradish 

Plumbago (Ceratostigma plumbaginoides) has not lost a beat to the heat. It's now beginning to bloom, about four weeks early. That's another consequence of the early spring. Photo.

Pokeweed (Phytolacca americana) This native North American "weed" is enjoyed by many for its stature (8' tall and wide is not unusual). It's also planted or tolerated for it attractive, bird-loved berries in late summer. European gardeners are specially fond of this species North Americans disdain, and so it's available in catalogs.LespedHeptN6703s.jpg

Purple bush clover (Lespedeza thunbergii) Full and right on schedule. It'll be our blooming star in September. Other than its usual trouble with potato leafhoppers, which produce the pale margins and eventual scorch known as hopper burn.
At right: An arrow marks the bush clover, growing alongside the equally stalwart white-barked seven son shrub (Heptacodium miconioides).

Red elder (Sambucus pubens) is a stand up guy. Its berries have all gone to the birds, who like them in any year but flock to them when rains fail. This red elder at right has "extra mulch" at its feet --- the dried remains of sweet woodruff (Galium odoratum) that could not tale the drought and heat.SambuGaliuN6713s.jpg

Rose of sharon (Hibiscus syriacus, photo) is fully cloaked in clean greenery and starting to bloom -- ahead of schedule, another product of the very early spring warm-up. It's putting to shame the dogwoods and hydrangeas in its vicinity.

Sage (Salvia officinalis) We should be clipping it and drying the new leaves that have grown since it finished bloom. They are almost certainly top notch in terms of flavor since the leaves create the flavorful oils as protection from heat and sun.

Sea kale's big blue leaves (Crambe maritima, photos) are a cool sight in hot weather, and its big cousin the giant crambe (C. cordifolia, photo) is also looking good (thanks to a deadheading two weeks ago).

Sea lavender (Limonium latifolium) Too bad its flower stalks toppled because otherwise the flowers dry in place and are attractive for more than a month.

Sedum 'Meteor' and other tall varieties of S. spectabile

Siebold viburnum (V. sieboldii, below, left) It's naturalized and become invasive in some parts of the country. We haven't seen that in Michigan but we can see it certainly can get by on its own.

Below, left: Siebold viburnum. Right: Ural false spirea and plumbago.

ViburnSiebN6708s.jpg SorbarN6685s.jpg

Spruce, Colorado blue

Tall coneflower (Rudbeckia maxima), a tallgrass prairie native.

Threadleaf bluestar (Amsonia hubrichtii, photo), spring blooming, it's grown right up over its seed pods now and will maintain its neat appearance until it blazes gold in late fall.

Ural false spirea (Sorbaria sorbifolia, above, right with plumbago) is a totally dependable, full blooming thug. The only consequence of drought and extreme heat seems to be blossoms that age and finish faster than usual. No matter -- we'll deadhead those branches and more flowers will come.

Weigela florida. Sustained themselves in tough conditions and simultaneously rebounded from our standard hard cut-back, four weeks ago at the end of their primary bloom season.

Below: It was on the basis of leaf size that we paired blue mist spireas (Caryopteris x clandonensis, background) with giant crambe (C. cordifolia, foreground, producing newleaves after having been cut-back after its bloom two weeks ago). The coarse crambe and fine Caryopteris are a visually pleasing pair, so it's even better than they both fare well in dry heat. Between the two they keep this bed looking good.


Below, left: Despite the drought, the catmints are growing back nicely after a hard cut-back. The plants were sprawled and covered a much larger area after their spring bloom -- outlined yellow. Now the plants are neat and on track to bloom again in a week or two.

Below, right: Curly chives (A), lambs ear (B) and late goldenrod (C).

NepetaN6707s.jpg cuchivesN6670s.jpg

Below, left: The fig tree seems to be enjoying this hot, dry summer, and is certainly ripening plenty of fruit.

Below, right: A blue-leaf form of switch grass (Panicum virgatum)

FigsFineN6650s.jpg PanicuN6680s.jpg

Below, left: Large flowered comfrey (Symphytum grandiflorum) is a tough, easy care groundcover that should be used more.

Below, right:Bearded iris, in front of elderberry.


Below, left: Threadleaf amsonia.

Below, right: Rose of sharon, leafy and happy. Other shrubs in the area, such as the panicle hydrangea on the left, are barely visible because they have so few leaves.

AmsoniN6695s.jpg HibisSyrN6638s.jpg

Below, left: Golden bleeding heart isn't looking gold since it stopped blooming early.Yet its fine blue green foliage and mounded form continue to make the dry shade garden look full. (We'd have listed our hostas 'Blue Cadet' as stars but their foliage had scorched edges. None of us could recall if that scorch dated from this year's unusual spring and frosts, or was more recent!)

Below, right: Even the just-rooted lavender cuttings are looking wonderful. We stuck the cuttings last November, snugging them up against this curb so they would have a bit of shade in the afternoon.

CorydLutN6688s.jpg LavCutngN6714s.jpg

Below, left: Sea kale, what a trooper. In spring this big foliage was pleasing, and subtended the bloom of Camassia 'Blue Danube.'  Then the plants bloomed white and fragrant and as they finished we cut them back to the ground. As it produced this second set of big leaves, blue California hyacinth bulbs (Tritelia laxa) bloomed around and through it.

Below, right: Bronze fennel (Foeniculum vulgare 'Purpureum') looks good right now with the large blue leaves of sea kale but its role is even more important at the end of summer. Then it will play the "smoke" to the "flame" of red salvia in what we call our campfire garden. So we're very glad it's held up well. As the days shorten and the red salvia come into their own that bed will be cookin.'

CrambMaN6646s.jpg FennCrambN6737s.jpg

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