Garden Notes: The hydrangea spectacular

And the color and gaiety of phlox.

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Hydrangea ‘Bloomstruck,’ hidden among the bracken. —Susan Safford

July ended on an odd note, with easy-sleeping low temperatures interspersed with some breathtakingly hot weather. The possibility of drought was held at bay, enabling Island-wide enjoyment of gardens, from extensive to pocket-size ones. Everyone marvels at the hydrangea spectacle this year.

Speaking of hydrangeas, a trial plant of Bailey Nurseries’ introduction ‘Bloomstruck’ arrived in my mail, somewhat bedraggled, a few years ago. This is a cultivar heavily endorsed by Michael Dirr and associates for all-around hardiness, performance, and attractiveness.

However, being in the heart of Island deer country, I did not foresee much likelihood for a future, let alone an actual flower, on the small, four-and-a-half-leaved waif. Available suitable space suggested a patch occupied by native bracken as a planting site.

Bracken, the ubiquitous native fern (Pteridium aquilinum and spp.), forms an understory in sloping parts of our place. Wading through it makes for tough going. Perhaps this would mask its presence and give the little ‘Bloomstruck’ a fighting chance?

So far, so good, and in this year of the 2017 Hydrangea Spectacular, the plant is covered with 15 compound blooms composed of smallish blue florets, supported by contrasting deep reddish stems that sport mid-green, toothed oval leaves. Now that I have counted and reported them, gardener’s superstition has me resigned to imminent deer harvest of these 15 blooms, but this afternoon I can spray them with repellent.

The garden party

Phlox paniculata, a beloved mainstay of the midseason garden, has joined the garden party, and is here with us now in sunny to part-shade borders. It adds color and gaiety: Bouquet makers as well as gardeners and hummingbirds rejoice.

Phlox paniculata, or garden phlox, is a member of the family Polemoniaceae, North American natives of Eastern and Central United States and Canada. It is not the first phlox of the season, but probably the one most depended upon for garden color, which forms the backbone of the perennial garden for those who can overcome its problematical aspects.

All members of the same family, phlox species appearing earlier in the season are the rock garden mats of creeping phlox, Phlox subulata, in white, shocking pink, and lavender blue; Phlox divaricata, blue woodland phlox; and Phlox maculata, the “wedding phlox,” which appears in June and is superficially similar to P. paniculata.

Older varieties, such as P. paniculata ‘Starfire,’ still perform well if given good growing conditions. —Susan Safford

The color range of phlox species is white–pale pink–lavender–cerise to deeper blues and purples. The exceptions to this “soft palette” are the so-called orange phloxes, such as P. paniculata ‘Orange Perfection,’ which are really a sort of hot neon salmon.

Phlox plants are capable of long lifespans, and horticultural lore contains many stories of discoveries of stands of them among the brambles at long-abandoned homesteads. Some of these were collected and rescued, and have entered the trade as tough survivor cultivars.

But try to grow it in decent surroundings and offer it the love and attention its beauty provokes — you will hear cries of dismay concerning snails, spider mites, and powdery mildew, not to mention the malevolent “phlox yellows.” Annoyance leads some gardeners to banish phlox, along with their bother, from the garden.

Here on Martha’s Vineyard, in contrast to, say, the muggy Mid-Atlantic region, limiting foliar moisture and overly moist conditions around and near crowns, and use of horticultural soaps or oils, and neem oil sprays, may control many of these problems. (bit.ly/phloxtoyellow)

Phlox grows in a range of pH; it likes moist but well-drained conditions. Avoid overcrowding: dividing crowns and respacing them when they increase in size improves beneficial airflow around plants. (Ironically, it is unlikely that anyone human ever divided and spaced those enduring survivors at the abandoned homesteads.)

Garden phlox has a high likelihood of self-seeding, as its flowers attract abundant pollinators. A few clones have shown the ability to come true from seed, but most exhibit a dismaying return to the primordial magenta. When cultivating or weeding around phlox, get rid of small seedling plants near parent clumps, since they will almost always be a different color — unless your inner plant breeder wants to experiment with what might emerge; perhaps the latest mildew-proof phlox sensation?

The cultivar most cited for mildew resistance is the stately white ‘David,’ (Perennial Plant of the Year for 2002) capable of heights as much as 40 inches. It was supposedly found as one of those chance seedlings I recommend getting rid of! The backdrop of lots of white flowers at the back of the perennial bed lends contrast to the garden party, heightening the color of other plants’ flowers and carrying well at dusk.

The Chicago Botanic Garden performed a comprehensive trial of garden phlox cultivars (bit.ly/phloxcomparativestudy). Check out the many entries’ performance and potential garden worthiness. (E.g., the trial found that variegated foliage forms of P. paniculata were in general weak.)

Cultivars resulting from recent breeding efforts have resulted in improved performance, as well as shorter forms that promise to eliminate the staking chore. The need for staking may also be reduced by a good chop earlier in the season, producing bushier, sturdier stems, although the price for this will be delayed bloom. Careful deadheading will also produce rebloom.

The other endearing quality of phlox I have yet to mention is fragrance. As we have seen, the perennial timetable appears to have brought forward the garden party over recent decades (Oriental lilies blooming in August a thing of the past), and retarded bloom of fragrant garden phlox may be a very happy coincidence for August entertaining.

Vegetable garden

Cure onions, garlic, and storage squash. Fit in another sowing of bush beans. bit.ly/controlwhatweeat links to a report from mercola.com about control of what we eat and what goes into our bodies, good reasons to have a home garden, save seed, and keep bees.