Get Out Your Summer Whites

Now that we’re past Memorial Day it seems like summer’s here, even if it doesn’t officially, astronomically, begin until June 21st. Everything in the garden is full, fresh and lush, especially after all the rain we’ve enjoyed this spring, and blooming plants are everywhere.
 
For the past few weeks our garden has been having a blue/purple moment, with Woodland Phlox, Forget-me-nots, Alliums, Amsonias and Irises going full out, juiced up by the sharp acid yellow of Euphorbias and the oranges and melons of the last Tulips. So there’s been lots of color, and very welcome after our long and dreary winter.
 
Now though, as the days warm and lengthen, white flowers suddenly seem to be everywhere, even on the fringes of the woods where native Viburnums, Elderberries and shrubby Dogwoods display their foamy white blossom. There’s something about white flowers that helps alleviate the heat, at least visually. Like a crisp linen shirt, white in the garden can be a refreshing and revitalizing antidote to the sultry weather that’s just around the corner.
 
Of course, early summer is prime time for Peonies and Bearded Iris, both of which have numerous cultivars in all imaginable shades of white, every one of them lovely. But in this post let’s look at some less obvious choices, in flower just now, that can bring the cool, soothing qualities of white to your garden just as the season turns.
 
Clematis, for instance, are coming on now. So many varieties in gorgeous jewel tones and delicious pastels, but the whites are very appealing too. I’ve tried several of them, and this one (above) has so far proven the most reliable. It’s ‘Guernsey Cream’, and so vigorous that I’ve been slicing off pieces of the root for the past five years and potting them up for giveaways. It opens ivory but soon bleaches to a pure clean white that has good substance, followed by decorative golden seed heads.  Another classic white is ‘Henryi’, with purplish brown stamens that add a note of contrast, but he’s more finicky, and sometimes goes down to fungal disease.

Baptisias have become popular garden plants, with many color permutations on the market. I like most of them, but if I had to choose only one to grow it would be this simple white species, Baptisia alba. It has a long season of interest, from early spring when it pushes up asparagus-like shoots of sooty grey-purple, through its clean flowering and good foliage, then ending with a fine display of rattling black seed pods. I can remember, in my distant youth down south, seeing this plant scattered among tall pines in poor sandy soil, so there’s no need to coddle it. The most challenging part is finding it for sale.

Of course, being a native southerner I have a weakness for Magnolias, so I’ve accumulated several kinds that can tolerate our northern winters. One of those is the Japanese species Magnolia sieboldii, known as the Oyama Magnolia. She’s an elegant thing with fragrant, pendant blossoms, satiny smooth but of substantial texture. The stamens can vary in color from pale pink to deep raspberry red, and the buds are egg-shaped. Just a lovely small tree that would be a good choice for a spot where space is limited. All the references give its hardiness as only to Zone 6, but mine is on year eight with no winter damage whatsoever, and I know of a much older specimen in Spencertown, the coldest part of the county.

I ran into this combination at the Berkshire Botanical Garden, and it perfectly illustrates the freshness that white can bring to a planting. It’s the variegated version of Solomon’s Seal, Polygonatum odoratum var. pluriflorum ‘Variegatum’ (whew!), underplanted with Sweet Woodruff, Galium odoratum. A simple, clean and foolproof combination that you’d be wise to copy for a shady spot with average to moist soil.

Another choice for the same conditions might be the Meadow Anemone, Anemone canadensis, but only for the wilder parts of the garden. In a border it can be too aggressive, but it’s just the ticket to provide weed-conquering masses in moist woodland or shrub borders. Native to the northern tier of the U.S. and to southern Canada, so you know it’s tough and well-adapted to our climate.

Planting American natives is all the rage now, but I still don’t see this one too often in the Northeast. Hopefully that will change as more people discover the Fringe Tree, or Grancy Greybeard as I heard it called growing up. The lacy flowers are like no other, and emit a light sweet scent, especially in the evening. Grows slowly to an ultimate height of about thirty feet, and the handsome leaves turn bright yellow in fall. Sometimes botanical names can be quite poetic… Chionanthus virginicus translates roughly as “Snow-flower of Virginia”.

Still another American native is the Cranberry Viburnum, Viburnum trilobum. ‘Wentworth’ is an outstanding selection that was originally discovered in New Hampshire, offering showier clusters of bright red berries and better fall color than the straight species. The beautiful lacecap flowers are out now, reason enough to grow it. Viburnums are native to many parts of the temperate world but North America is rich in species, so they should be grown more, even though the Viburnum Leaf Beetle has become a threat to some types. I’ve had a few show up every year, but so far, not enough to disfigure my plants to any alarming degree.

I’m planting lots of the native American Sedges these days, but the first Carex to come into gardeners’ consciousness, about twenty-five years ago, were the Asian species. This is the first one I ever tried, and I still have it today… it’s Carex siderosticha ‘Variegata’. The bamboo-like leaves are cleanly variegated with white and arise from a gradually (not invasively) creeping rootstock that will ultimately form a tight groundcover in moist shady ground. Lovely combined with solid green Hostas, Dwarf Goatsbeard, Ferns or Heuchera ‘Autumn Bride’.
 

Confession:  I’m a plant snob but not a collector of rare or unusual things for their own sake. I’d much rather grow something that’s a good doer and solves a problem, than give space to a struggling rarity. So yes, I have a large patch of this white variegated Hosta that’s as common as pig tracks, as my grandfather would have said. In fact it’s so ubiquitous around here that I’ve never bothered to find out its name, but it must be an older variety because it’s seen at nearly every farmhouse and suburban ranch in the Hudson Valley… a true pass-along plant. When it emerges in spring the white variegation is much creamier, so I underplanted it with one of my favorite early Daffodils, the pale yellow ‘W.P. Milner’, and I love the combination. And this Hosta increases so fast that from my original five-year-old clump, I was able to get enough divisions to cover a sizeable area under a Maple and next to a big mass of Hydrangea ‘White Dome’, where it looks fresh and clean all season and does a fine job of suppressing weeds. So there.

A full month after our American Dogwood blooms, the Asian species begin to flower. They are, in my opinion, less spectacular than our native tree, but very beautiful in a different way, displaying their pointed, star-shaped flowers against the already unfolded foliage. As with our native Dogwood, the “flowers” are actually showy bracts that surround the true flowers, the golden central cluster of stamens and pistils. There are many cultivars, some of them pink, but I grow a simple white one, Cornus kousa var. chinensis. All of them are small trees of multi-season interest, with early summer flowers, interesting showy fruit, and good fall color.

Siberian Iris are having their brief but spectacular moment just now, and one that I’ve enjoyed for many years is this dwarf white, Iris siberica ‘Nana Alba’. It’s as easy as any Siberian Iris and the shorter foliage means it doesn’t flop later in the summer like so many of the taller varieties do. Besides being beautiful and vigorous, another reason I like having it around is that my plants originally came from the late, lamented Heronswood Nursery, whose annual catalog (with no pictures whatsoever) was eagerly anticipated by plant nerds across the country. It’s one of only three or four things I still have from there, despite having ordered many more than that over the years, and failing to keep them happy. So it’s a nice, humbling reminder.
 

Lately I’ve been on a somewhat obsessive binge with the perennial Geraniums, and have been trying several new ones each year. Most of them come in shades of pink, blue or purple, but there are a few that are true whites, making them doubly useful as fillers and weavers among other perennials, which is what Cranesbills do so well. Very well adapted to our climate is this white selection of our native Geranium maculatum, called ‘Hazel Gallagher’. I don’t know who Hazel was, but she must have been a fine gal because her namesake plant is top-notch.   
 

Another great white perennial Geranium is this one, Geranium sanguineum ‘Album’. Delicate foliage spangled by clean white blooms and easy, easy, easy. In fact this is one of the longest surviving perennials I have, going back to my community garden days in the East Village of the late 80’s. Geranium sanguineum, the Bloody Cranesbill, is probably the most common hardy Geranium seen in American gardens, in its magenta form. The white is sooo much nicer.
 

We’re lucky to have a little stream at the edge of our property, into which many acres of woods drain, so it has water flowing most of the year. It makes the perfect habitat for many things that like shade and constant moisture, including Primula japonica, one of the Candelabra Primroses, so called for its gradually unfolding tiers of flowers. They reseed reliably where happy, and I think I started out with a pure white selection called ‘Postford White’. But they are promiscuous things, and whatever color you choose, you’re eventually liable to end up with a range from white through all shades of pink to magenta. They’re all so lovely I don’t have the heart to rogue out the colors I don’t prefer, so it’s always a surprise to see what comes out.   
 

One of my favorite recent acquisitions is this Sweet-shrub, Calycanthus x ‘Venus’, a complex hybrid of several species including the reddish-brown flowered Sweet Betsy from the southeastern U.S. It’s a spreading, multi-stemmed deciduous shrub that in late May bears luscious Magnolia-like blossoms, 3-4 inches across, that have the scent of ripe strawberries and melon. The flowers are pure white, of waxy substance, and have distinctive yellow and purple structures at the center. Truly looks like nothing else and always gets attention. Needs shade from the hot afternoon sun and reliably moist soil, but otherwise it’s not demanding. The foliage is a rich, glossy green and turns a nice shade of golden yellow in the fall.
 

Mock-orange, or Philadelphus, is a rather forgotten shrub nowadays, and it’s a pity. It has sweetly scented flowers and a lovely arching form that makes it look perfectly at home around an old farmhouse. In fact it’s one of those plants that was hugely popular in the 19th century, with many named varieties developed by Victor Lemoine, the French hybridizer responsible for almost all our beautiful old Lilac cultivars.  But Mock-orange doesn’t lend itself to being pruned into a green meatball, so it’s never been a darling of “landscapers” or the kind of home gardeners who prefer over-tidy foundation plantings. Also, its period of bloom is glorious but brief, so although it looks respectable all year, it could never be considered a four-season plant.
Nevertheless, I love them, partly because I still grow one, Philadelphus grandiflorus, (above) that’s descended from my grandmother’s plant. In the south we call it English Dogwood, although it’s neither English nor a Dogwood, and because it suckers freely it’s often shared around among gardeners. The flowers are larger than other Mock-oranges but only slightly fragrant.

Much richer in scent are the smaller flowered hybrids, some of them doubles (above, a cultivar I’ve grown for years but have lost the name of) or the single species Philadelphus coronarius (bottom of this post). There’s also a variety with golden leaves, but I’ve never seen it except in photos, and although it certainly would provide more foliage color, I’m not sure the white flowers show up as nicely against the lime-green leaves as they do on the standard dark green kinds.

Another of my favorites is ‘Belle Etoile’ (above), a shorter cultivar sporting single white flowers beautifully marked with purple near the central boss of stamens. Whatever the variety, Mock-oranges should only be pruned by taking out a few of the oldest canes from the base every year to preserve their distinctive fountain-like habit. Never, ever cut them back halfway or attempt to shape them unnaturally.
 
By the time I’ve finished writing this piece, some of these plants will have already passed out of bloom… it’s early June, after all, and the flowering sequence is hurtling forward, another round of things that like it even warmer are budding up, waiting for their moment to bloom. But that’s the way gardens work, and what they have to teach us about the passage of time, about life itself. Right now I’m enjoying this lush, fragrant, exhilarating moment… my very favorite time of the year, when spring surrenders, so gracefully, to summer.