Undemanding summer bloomers

Russian sage (Perovskia atriplicifolia, below) typically grows with a slightly arching, upright habit, but that’s when it’s properly sited in full sun, and not jammed beneath a crapemyrtle and crammed under a wide spreading Joe Pye weed. It deserves better, but no matter, it seems happy enough in my garden. It has flowered since the start of summer, though its stems arch heavily towards the ground. The soil in this spot is lean and dry, but Russian sage is undemanding, and perhaps would resent richer soil with more moisture.

There are plants that thrive in the heat of summer, and seem not to mind infrequent rainfall. Russian sage is certainly one of these, and despite inhospitable conditions it displays its small blue flowers through much of the summer. The blue-green foliage is small and doesn’t make much of a show, but the the upright habit and long period of bloom make Russian sage an ideal perennial for a sunny spot between broad leaf shrubs or slow growing perennials.

Years ago I planted a few butterfly bushes (Buddleia) at the back of the garden where the soil alternates between saturated and bone dry in late summer. The common ‘Black Knight’ languished, growing and flowering, but never seeming to be happy. It grew tall and lankly, and eventually I was convinced to chop it out. Though I never saw a seedling, it was about this time that word got around that butterfly bush was invasive, so I hesitated to plant another in a drier part of the garden. But, recent introductions have a considerably more compact habit and are sterile, so I decided to plant a few of the new varieties.

I’ve been quite pleased with ‘Miss Ruby’ (above), which grows compactly to about four feet tall and wide. It has been flowering for a few months now, with no end in sight. And, because there are few areas of mostly full sun remaining in the garden, it’s planted in nearly the same spot where ‘Black Knight’ was a disappointment. I’ve heard reports that the ‘Miss Molly’ grows and flowers in a similar manner.

I had high hopes when I first planted the very compact growing ‘Blue Chip’ butterfly bush (above), but I’ve been slightly disappointed in its performance. There’s no doubt that it is more compact and smaller than others, but it lacks vigor by comparison. ‘Blue Chip’ is in slightly damper soil than ‘Miss Ruby’ so this could possibly explain its mediocre growth, but I’ve not been overly impressed seeing it in other gardens. So, I’ll be trying some other low growing butterfly bushes in the next year to see if their performance is superior.

In the past few years there have been a number new introductions of the old time, summer flowering glossy abelia. The recently introduced cultivars have improved foliage color and more compact growth, but I’ve found that the small flower clusters often don’t stand out as much on the variegated and yellow leafed types (Abelia x grandiflora ‘Canyon Creek’, above). ‘Kaleidoscope’, with yellow and green variegation and a very compact habit, seems to be the best of the lot, and is perhaps more useful as a foliage plant than for its flowers.

Though gardenias have splendid dark green foliage, the scented blooms are clearly their best feature. The problem for mid Atlantic gardeners is that they have been very marginally cold hardy. Despite cultivar names that indicate cold hardiness, until the last few years I’d never seen a plant that had survived a winter. Now, with inordinately warm winters (and new varieties that promise cold hardiness well below zero degrees) I’ve had gardenias survive through two winters. ‘Pinwheel’ (Gardenia augusta ‘Pinwheel’, above) has flowered off and on through the summer, and I’ll be planting a few other cultivars to give them a try. Unfortunately, with my poor sense of smell I’m not able to enjoy their scent, but the hardy gardenias are delightful shrubs even without the fragrant blooms.

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In late August

There’s an obvious void in the rear garden where the multi trunked Seven Son Tree (Heptacodium miconiodes, below) was toppled over by a storm earlier in the summer. The missing tree disturbs my eye, and I’ve been desperate to replace it, but hesitant to plant another tree until cooler temperatures and more regular rainfall returns in September.

I think I might have finally settled on a replacement after much consternation. I was convinced for a short while that the splendid purple ‘Catawba’ crapemyrtle was the right tree, and it is certainly the appropriate size for the spot. Then, I saw a Korean Sweetheart Tree (Euscaphis japonica), which is similar in some ways to the Seven Son, but possibly even more beautiful. For a few days I was excited that I’d found the perfect tree, but then I couldn’t figure out how to get one, at least one of adequate size. So, I decided to buy a little one to grow along in a pot for a few years until I figure out another spot for it, and I’ve settled (at least for today) on planting a red horsechestnut (Aesculus × carnea). Eventually it will grow a bit too large for the spot, but that will be long after I’m gone, and it’s such a magnificent tree that the garden’s next owner is certain to be delighted.

When the Seven Son tree snapped at ground level it fell and damaged roses (‘Homerun’ rose doing better with more sun, above) and perennials (Agastache ‘Golden Jubilee’, also better in full sun, below) that have mostly recovered by now, but hostas and toad lilies in the suddenly sunny spot were fried. They’ve begun to rebound slightly, but won’t recover fully until spring. The horsechestnut is low branched and wide spreading, so even though it’s quite slow growing the tree will begin to provide some immediate shade.

There’s always something for the gardener to fret about in the heat of summer, and after record high temperatures in June and July more than a few plants are a bit off color or crispy around the edges. But, when these just barely more than a few plants and the open space where the Seven Son tree was planted are ignored, the garden is doing quite well. There’s not really any reason to be depressed, and certainly I’m looking forward to some new planting in September.

The Cape fuchsia (Phygelius capensis) narrowly escaped the toppling Seven Son tree, and it doesn’t seem to mind sun or partial shade, so it’s growing and blooming as if nothing happened. Cape fuchsia is not a fuchsia at all, but the flowers are somewhat similar to the less cold hardy fuchsias. I’ve planted several in the garden, one with yellow-green blooms (above) that flowers sporadically, and the other pink (below), that flowers for most of the summer (and seems undeterred by heat and drought). Both are a bit floppy with branches draped over and through neighbors, but they’re dependable bloomers through the summer.

Last year I planted pink turtleheads (Chelone lyonii ‘Hot Lips’, below) in semi damp ground just at the start of a tiny sliver of a spring that winds its way to the back of the garden. This spot is mostly shady, with perhaps a few fleeting moments of direct sunlight, and this has proved to be an ideal setting. The turtleheads are growing robustly, with no sign of stress from heat or drought though the spring has mostly dried for the summer.

The foliage is rich and dark, the flowers delightful, and if all goes well they will seed so there will be little pink turtleheads sprouting all about this damp, shady area in the spring.

Filling in the blanks

The spring after planting ‘Crystal Falls’ mondo grass (Ophiopogon jaburan ‘Crystal Falls’, below) I cut its slightly weather beaten foliage back to the ground, just like I do with liriopes. I’ve also planted dwarf mondo grass (which I don’t cut back unless it is severely damaged by the winter) and black mondo (that doesn’t seem to suffer any injury due to the winter), but the tall ‘Crystal Falls’ seemed more similar to liriopes. The few times I’ve cut dwarf mondo back it seemed to take forever to recover, and I learned with ‘Crystal Falls’ that this is likely to be a trait shared by other mondo grasses.

After being cut back, no growth was evident at the end of May, and I can’t recall precisely, but I don’t believe there was any new growth until July (maybe). In any case, I decided that this would be the last time I’d cut back ‘Crystal Falls’, and if it looked bad again next spring perhaps it would be better to dig it out and forget about it. Fortunately, the next two winters have not damaged the foliage to an extent worth worrying about, so it’s still here, and in late August it’s blooming.

‘Crystal Falls’ is considerably taller than other mondo grasses (Ophiopogon planiscapus ‘Nigrescens’, black mondo, above), and taller than the common liriopes. I’ve seen it planted in nearly full sun, and in fairly heavy shade, and it looks much happier in the shade. Both sun and shaded plants flower at about the same time, but the foliage of the mondo grasses in part shade is much greener and more vigorous looking. The sun grown mondo has grown fuller, so it grows faster with more sun, but the foliage is stressed by the heat and sun.

‘Crystal Falls’ (and other mondo grasses for that matter) are great filler plants between shrubs and tall perennials. They also work well standing alone as a tall border edger, but they shine when plugged into a gap between large leafed hostas and broadleaf evergreens. The arching flower spikes of ‘Crystal Falls’ stand taller than the foliage, so the blooms stand out more than other mondo grasses or liriopes.

For spaces between smaller shrubs and perennials, or for massing, liriopes are very useful, both in sun and shade. The green leafed ‘Big Blue’ (Liriope muscari ‘Big Blue’, above) is nearly evergreen in my garden, with only minor foliage damage in typical winters, but the foliage of variegated types (below) is usually damaged so that it must be cut to the ground each spring. The liriopes are now flowering in the garden, and their blooms are a delightful, rich purple.

I’ve also planted the almost white flowering, spreading liriope (Liriope spicata, below) in difficult areas where I want to fill a space. This is a plant that’s aggressive enough to be considered a nuisance, though not to the point to be called invasive. In my garden I must monitor my wife whenever she ventures out to be sure she’s not digging it out of one spot or another. Her aversion to spreading plants lumps liriope and running bamboos into one category, regardless of how easily they are controlled.

In fact, the spreading liriope is not as attractive as the clumping forms in either foliage or flower. It is a handy plant for difficult spaces, but Liriope muscari and mondo grasses are superior for filling smaller spaces or for edging beds.

The blue mist of late summer

In one year ‘Hint of Gold’ blue mist shrub (Caryopteris x clandonensis ‘Lisaura’, above) has grown from hardly more than a rooted cutting to three feet across and nearly as tall. Its branches are more rigid and its form more compact than other blue mists in the garden, and foliage retains its yellow color through the heat of summer. I’ve planted Worcester Gold (Caryopteris x clandonensis ‘Worcester Gold’, below) and ‘Sunshine Blue’, and these often fade a bit by mid summer. The foliage of ‘Hint of Gold’ has a thicker substance, and it has faded only slightly.

The flowers of ‘Hint of Gold’ are similar to other blue mist shrubs (but lighter in color than ‘Dark Knight’, below), with small, lacy blooms clustered at the base of each group of leaves. A mass planting of caryopteris is stunning in late summer, but I’ve plugged single plants into various sunny spots that were too green otherwise and needed a bit of summer color. A few older blue mist shrubs have begun to fade as shade has encroached, so this is a plant that requires nearly full sun.  

At the same time as ‘Hint of Gold’, I planted the variegated leaf ‘White Surprise’ (Caryopteris x clandonensis ‘White Surprise’ below), and it has grown much more slowly in a slightly shaded location where its foliage is more important than flowers. This spot is also a bit damp, and though ‘White Surprise’ is alive and healthy, I have some question that it might prefer drier soil. It flowered a year ago, and I’ve no doubt that it will bloom again in the next few weeks, but it will take a little longer for this slower growing blue mist to make much of an impact.

The branches of semi shrubs like blue mist are typically cut back by half in early spring, but the stems of the variegated leaf ‘Snow Fairy’ blue mist shrub (Caryopteris divaricata ‘Snow Fairy’, below) are less woody, and are cut off just above the base like a perennial. The foliage of ‘Snow Fairy’ is similar to ‘White Surprise’, but the flowers are later and less substantial. 

I’ve had to do some aggressive pruning to rescue ‘Snow Fairy’ this summer. A neighboring oakleaf hydrangea had lived harmoniously in close proximity for several years, but this spring it decided to expand its territory to grow much wider. ‘Snow Fairy’ was losing the battle until I cut out several branches of the hydrangea to give it a bit more space. I’ll have to take care in future springs to make sure that room is carved out so this splendid blue mist shrub isn’t lost.

I can’t believe they ate the whole thing

Walking around the garden after this afternoon’s light rain I noticed that one of the small weeping Golden Chain trees (Laburnum x watereri ‘Pendulum) was mostly defoliated. Heat? Drought? No, I looked closer to find a few handfuls of caterpillars (White-marked tussock moth caterpillar, below) actively munching on the few remaining leaves. I supposed that the white protrusions on the backs of the caterpillars were wasp larvae like I’ve seen on hornworms, but a bit of research by my wife revealed that these are tufts of white hair.

Nevertheless, a solitary wasp was on the prowl, moving the length of each branch (looking for caterpillars, I suppose). I lingered for quite awhile to see what would happen, until the agitated wasp gave me enough dirty looks that I figured I’d best retreat. After a few minutes I returned with a twig to dislodge the caterpillars, and hopefully save the last few leaves. I dared not swat them away by hand. I noticed that the caterpillars had antenna-like protrusions and spines, and in the past I’ve brushed against these to receive a mildly paralyzing sting.

I noticed a second group of four hairy, red caterpillars on the tree, but these were not actively eating leaves at the moment. They were flicked off onto the ground below as well, and I’ll check tomorrow to see if they have made their way back into the tree. In the middle of August I’m not too concerned that the tree will be weakened by the loss of foliage, but I thought it best to avoid losing every leaf.

Along the wooded edge of the garden several small red mulberries are currently infested by fall webworms. In a similar manner these caterpillars have stripped the trees nearly bare, but the mulberries are a bit of a nuisance that I must regularly prune to keep them out of nearby magnolia and dogwood. I occasionally consider taking a few minutes to chopping them out, but there’s always something to be done that involves less labor, so there they stand. It wouldn’t hurt my heart if the caterpillars were to kill the mulberries, but I doubt it will come to that, and the caterpillars are unlikely to spread to the other trees. Both the mulberry and Golden Chain trees will probably have stored enough reserves to survive until spring without foliage.

I don’t think there’s much of a lesson to be learned from this experience. I’ve not sprayed pesticides for bugs of any sort in years, and caterpillars are easily controlled if they are observed early on. I’ve walked past the Golden Chain tree dozens of times over the past week or two when the caterpillars would have begun chowing down, so the blame here is on my lack of attention. With a small number of caterpillars they can be hand picked (or flicked to ground with a stick if you’re afraid of them like I am), and tent caterpillars and webworms can be dislodged with a stick or with a spray of water. The damage they inflict is usually not fatal, in particular when the damage is done at the tail end of the season.

The summer blooming hydrangeas

A seedling of Tardiva hydrangea (Hydrangea paniculata ‘Tardiva’, below) has popped up in the middle of the lacecap ‘Twist-n-Shout’ (Hydrangea macrophylla ‘Twist-n-Shout’) . ‘Tardiva’ is a cultivar, so it’s unlikely that the seedling will be identical to the parent plant, but it appears to be very close in appearance. The more pertinent question is, should the seedling be allowed to grow up through the other hydrangea, since panicled hydrangeas grow many time larger than mopheads so that the smaller plant will quickly be overwhelmed?

Of course, there is no sense in leaving both hydrangeas, and since the parent ‘Tardiva’ is only a few feet away it makes perfect sense to pluck the seedling out. But … as the seedling grew up through the lacecap it was shaded so there are no branches for the first few feet. Then the main stem divides into three, and there are flowers on each of them that stand about four feet tall.

Panicled hydrangeas are easily made into small trees, so I’ve considered growing the seedling as a small tree with the lacecap growing at its base. I know, the idea is ludicrous! The seedling will grow and flop over the smaller hydrangea, which will be lost. But, I’ve done stupider things. Lots of times! So, I’ll let it go for a year. If it blows up and the lacecap is lost you can be certain never to hear about it again, but if this turns to something remarkable …. Anyway, I’ll probably cut it out in the spring, and of course it will be best if it’s removed long before the roots are hopelessly intertwined with the lacecap’s.

As I’ve said, panicled hydrangeas grow quite large, to nearly ten feet tall and wide, and they are to be treasured because one large shrub will have hundreds of large, creamy white blooms. I planted ‘Tardiva’ a number of years ago, but in recent years there have been a number of superior introductions, notably the chartreuse flowered ‘Limelight’ that fades to white. The flowers of panicled hydrangeas are effective for a month or longer, and blooms that persist through the winter are still somewhat ornamental.

Unfortunately, I’ve planted ‘Limelight’ so that it is barely visible from anywhere else in the garden unless you are to muddle through the swampy overflow of the dirt bottom, wet weather pond at the back of the garden, and then duck under the low hanging branches of the river birch (the one with leaves being eaten by sawfly larvae). Panicled hydrangeas prefer full sunlight, but this one is shaded and squeezed by larger trees, and no matter how vigorous it will eventually lose out to the huge bald cypresses and another river birch planted only a few feet away.

I’ve run out of excuses for today on why I plant things where they don’t belong, so we’ll just say that I planted these when I was young and dumb, and we’ll pretend for a few paragraphs that I don’t do those kind of things anymore. If I had to start things over I would plant a hedge of the various panicled hydrangeas along one one sunny border or the other, at least four or five plants each of three or four cultivars. The shrubs would provide only a minimal screen though the winter and early spring, but the foliage is pleasant, and when flowers arrived in midsummer the sight would be quite splendid for several months.

But, I have no intention to bulldoze the rear garden and start over, and what’s there instead is still quite wonderful without fifteen or twenty hydrangeas with thousands of creamy white flowers. Still, I’ve done stupider things.

Rebloomers

I don’t pretend to understand the environmental factors that determine when flower buds are formed on plants, or how quickly reblooming plants reset flower buds. It seems that temperature is the primary influence for many plants to set flower buds, but other plants are more effected by hours of daylight.

I’m quite certain that I’ve heard someone (or lots of someones) declare for the past fifty years that whatever year we’re in has had the most unusual weather ever. Of course, there’s always something peculiar about that year’s weather, but by year’s end most are very average. Except this year! In this statistically warmest year ever, far above average winter and early spring temperatures have caused many plants to flower weeks ahead of schedule, and for plants that rebloom this has added complications.

In last year’s unusually mild late autumn Encore azaleas flowered through November, and ‘Autumn Amethyst’ had a few blooms remaining in early December in my northwestern Virginia garden. Still, the Encores set new buds to flower in late March, a month earlier than normal. In the deep south Encore azaleas flower early enough that they often reset buds to bloom again in mid summer, and then again in the autumn, but in more northern areas they flower in the spring and again in late summer extending into early autumn.

In early August the flowers on ‘Autumn Twist’ are struggling with the extreme heat. ‘Twist’ is the most dependable and longest lasting autumn bloomer in my garden, but the flowers melt quickly in one hundred degree heat. Occasionally, I’ve had flowers on a few Encores late in the month, but these are several weeks early. Fortunately, other Encores are not flowering yet, so there will still be a good floral display in September and October. Is ‘Twist’ flowering early enough to reset buds by late autumn? Perhaps if November and December are as warm as the months were last year, but I wouldn’t bet on it.

The reblooming hydrangeas typically flower late in the spring, and often have sporadic blooms through the summer. With the extreme heat this year they have been slow to reset buds for the late summer bloom, so I expect this will be a bit later this year than is usual. I’m quite certain that the lack of bud set is a result of the hot temperatures. In a few mild summers the hydrangeas have reset buds to flower through July and August, but this year blooms have been scarce in the summer months.

In the past week temperatures have turned a bit more moderate and rainfall has picked up, so I expect the hydrangeas to get going setting buds that will flower late in September, only a little tardy. With less severe heat the Encore azaleas with fat buds but no flowers are likely to pop into bloom very soon.