© Janet Davis
I’m a Leo, and female Leos,
I recall one astrologer saying, are latent exhibitionists. Now, I’ve never
joined a nudist colony or hankered to see my name in lights but when it comes to
the garden, I’m Leo to the core. In other words, no matter how much I try to be
subtle in my plant choices, in the end I veer to “gauche, gaudy, garish and
gimme-more-in-a-brighter color”.
In the August
garden, nothing tickles an exhibitionist’s fancy like the huge, silky blossoms
of the hardy perennial rose or swamp mallow, Hibiscus moscheutos. The nice surprise is that a plant so
tropical looking is actually very hardy and tolerates our cold winters well.
Native to salt and
freshwater marshes from Massachusetts and Michigan south to Florida and
Alabama, rose mallow naturally loves moisture and humidity. In the garden, it
thrives in sunny, damp soil; if grown in a border, it needs rich soil that’s
never allowed to dry out. Because of its southern origins, it puts on its best
flowering show when summer is long and hot.
The strain “Southern Belle”
grows to about four feet, and occasionally taller in really damp soil. Flower colors are white, rose, pink and red,
the light ones usually having a crimson center. The ‘Galaxy’ strain is ‘Lord
Baltimore’ is a stunning red, ‘Lady Baltimore’ is pink with a darker eye and
‘Blue River II’ is shimmering white.
Rose mallow is very easily
grown, even from seed and it transplants well from a nursery pot, provided it’s
planted in spring or early summer so roots have a chance to establish. Whether
seed-started, grown from cuttings (which guarantees you the same color) or
purchased as a pot plant, it’s best to protect rose mallow during its first
winter by mulching well. But don’t give up hope if you don’t see it in spring –
it’s notoriously late to sprout through the soil.
The
big trend now is to do selective pruning on many perennials to stagger
flowering heights, improve flowering by increasing flowering stems and delay
flowering time a little. With rose mallow, you can trim a few of the tall,
sturdy shoots back by about 1/3 in early summer to extend the flowering time.
But even if you don’t do that, the plant will still bloom over a relatively
long period in August and September.
With its flamboyant
blossoms, swamp mallow needs to be shown off, not jammed in with lots of other
late-summer flowers that will steall its thunder. Ornamental grasses make a perfect backdrop, particularly any of the
moisture loving miscanthus species. So
does a carpet of coleus, particularly when the color is chosen to enhance the
swamp mallow. The dull burgundy flowers
of taller Joe Pye weed, Euupatorium
purpureum, look good too. Moisture-loving obedient plant, Physostegia virginiana, though shorter,
offers a good contrast in form; its wand-like purple spikes are particularly
attractive with the light pink rose mallow. And then there are hostas, all of
which make a nice foreground planting and like the same moist conditions.
My favorite use of swamp
mallow is at Chicago Botanic Garden’s Evening Island. Here designers James Van Sweden and Wolfgang Oehme have used the
big blossoms as dramatic accents -- masses of pink ‘Lady Baltimore’ in a damp meadow;
‘Lord Baltimre’ with blue caryopteris; and white ‘Blue River II’ paired with Cleome
‘Sparkler White’ in a spectacular field of ruby-red ‘Shenandoah’ switch
grass (Panicum virgatum). Talk
about exhibitionism!
Adapted from a column that appeared originally in the Toronto Sun
.