Eleven Garden Giants

by Colleen O’Neill Nice

I love a soft, cool rain. My gardens love it too. But not all plants flourish in a wet sunless environment. So, when strolling through my woodland borders, I was captivated by the giants of the garden who absolutely thrived in all the rain. While many gardeners were complaining about powdery mildew on their peonies and leaf spot on their zinnias, I was frolicking amongst my mammoth monsters that seemed to grow overnight. Given ample room and moist conditions, these prodigious perennials created a tropical effect, adding drama with a frenzy of foliage.

Arching over the pulmonaria and hosta,

the thick stems of Astilboides tabularis

(formerly known as Rodgersia tabularis)

support huge shield-like leaves.

The bright green leaf surface

has a sandpaper texture

with numerous small teeth

projecting from the undulating

leaf margins. In addition to the

strikingly bold foliage, creamy

white panicles rise upward in July,

on tall stems. A single specimen

can reach three to four feet in height

and width, so ample room should be

allowed when siting this plant. Astilboides is a

low maintenance, clump-forming perennial that prefers cool, moist soil in partial shade. It can be divided in the spring, as the foliage emerges, or propagated from seed in the fall.

I use the handsome large-leafed Rodgersia aesculifolia in my garden

to help camouflage the gap left by my bleeding hearts after they go dormant for the summer. This rodgersia has palmate leaves that resemble those of a horse chestnut. Each leaflet is coursely toothed, strongly textured and about seven inches long. In July, white flowers bloom on upright, two-foot tall stems, while the overall height of the plant can reach four feet. Rodgersias prefer morning sun and moist soil

with plenty of organic matter.

Finely-textured plants like ferns,

corydalis or astilbe are a suitable

contrast for the robust foliage

of this perennial. Propagate

rodgersia by division in

early spring or by starting seeds

in a cold frame.

Hosta ‘Big Daddy’ is a real

showstopper and gets plenty

of attention in my garden.

The enormous frosty blue leaves

are cupped and thickly quilted,

so slugs are not a threat. In July, white

bell-shaped flowers poke up through the foliage. Like most hostas, ‘Big Daddy’ prefers partial to full shade and regular watering. It grows about three feet tall and four feet wide, shading out weeds as it matures. It is a tough plant and tolerates drought as well as sandy or clay soils. I prefer to divide ‘Big Daddy’ in the spring before foliage emerges, but fall division works as well. In October, I delight

in collecting ripe seeds from

‘Big Daddy’ which are always

quick to germinate. Since hosta

seeds do not usually come true

to the parent, I often get a mix

of blue, green and gold babies.

The grey-blue foliage of

this specimen is a great

companion for my finely

dissected red-leafed

Japanese Maple.

Often called the umbrella plant,

Darmera peltata thrives on moisture.

Pink flowers emerge in early spring

from leafless, hairy stems. As the

flowers fade, enormous, upswept,

umbrella-like foliage enlarges

up to 24” across. The dark green

leaves are rounded, deeply

lobed and toothed, with

conspicuous veining. The

vase-shaped clump, four feet tall

by three feet wide, can be divided

in spring or fall. A fast grower,

it needs constant moisture

in a part to full shade setting.

A native of the western U.S.,

darmera is hardy in zones 5-7, and creates

a distinct, fresh look in my woodland border.

Romping through my garden is the infamous

Petasites japonicus ‘Variegata’

or giant Japanese  butterbur

(I call it dinosaur food, for short). 

Its large green flowers bloom

close to the ground in

early spring, with leaves

appearing soon after. I often

caution people about this plant

before they put it in their gardens,

but no one ever heeds my warnings.

The three to four foot wide leaves,

covered with brushstrokes of pale

yellow, cream and green, are just too

seducing to pass up. This giant can be

very aggressive, traveling by underground

rope-like rhizomes, pushing its way through plant roots just to get closer to a sprinkler head. It is by no means low maintenance if planted amongst other more polite perennials. Once or twice a season, I thin out petacites to give its neighbors –  ferns, hostas, baneberry and dicentra  – a fighting chance. Hardy in zones 5 to 9, it can reach three to four feet tall in wet summers. You probably won’t need to propagate more of this plant, but just in case, two-inch rhizome sections will sprout into new plants. The stalks and flower buds are edible.

A noteworthy complement to

Hosta ‘Big Daddy’ is Hosta ‘Sagae’

with its frosted blue-green leaves

edged in yellow. Grey-green

streaks are painted in the areas

between the leaf’s center and

its margins. The impressive

upright mound consists of

thick, triangular, slug-resistant

foliage. In midsummer, lavender

flowers rise up on four foot tall

scapes. ‘Sagae’ grows three feet tall

and five feet wide in rich, consistently

moist soil. It prefers light sun to full shade

with leaf margins fading to cream in the sun. It grows very deep roots, so plant it in a good location and leave it alone for few years so it can reach its mature size.

For a strong vertical accent,

Dryopteris tokyoensis is a perfect

addition to the shade garden.

The Tokyo wood fern's ladderlike,

upright fronds form vase-shaped

clumps that grow to four feet tall

in moist soil. It is a low

maintenance, moderate grower

that prefers light to full shade

in a sheltered habitat. This

easy-to-grow, relatively unknown,

deciduous fern from Japan is hardy

in zones 4-9. It is easily propagated

from ripe spores or divided in the spring

or fall. It is truly impressive arching over hostas, begonias or dicentra.

My favorite large hosta for

dividing areas in my garden

is Hosta ‘Nigrescens’. Its immense,

grey-green leaves form a

very upright vase shape

and several plants spaced out

in a row can create a hedge

effect. Its broad, cupped and

corrugated foliage is thick and

slug resistant. In August,

pale lavender flowers can reach

seven to eight feet, one of the

tallest scapes of any hosta. Hardy in

zones 3-8, ‘Nigrescens’ needs to be

watered regularly in a partial to full shade

environment. At maturity, it can grow three feet tall by six feet wide. For seed propagation, allow pods to dry on the plant, then break open the pods to collect the seeds.

The largest of the northeastern

native wood ferns,

Dryopteris ‘Goldiana’

(Goldie's Wood Fern) reaches

four feet tall in ideal conditions.

It is a bold, somewhat coarse fern,

forming large clusters of graceful

arching fronds. Broad,

oblong-triangular foliage arises

from a vase-like clump that

spreads slowly by creeping rhizomes.

Named for Scottish botanist John Goldie,

its fronds are green without a hint of gold.

This easy-to-grow deciduous fern prefers

a dappled shady moisture-retentive woodland site.

It is hardy in zones 3-8 and is very attractive planted in masses where strong, bold texture is desired.

Symphytum officinale is a colossal,

perennial herb which is a particularly

valuable source of fertility for the

organic gardener. Also known as

comfrey, its very deep roots mine

a variety of nutrients from the soil.

The nutrients are then made

available through its large, fast

growing leaves which quickly

break down into a thick black liquid.

The leaves of comfrey contain 2-3

times more potassium than farmyard

manure. Comfrey can be used as a

compost activator, a liquid fertilizer,

a side dressing or added directly to your potting soil. It grows two to three feet tall and four to five feet wide in full sun and is hardy in zones 4-9. Tiny purple flowers in summer are an added bonus. I usually harvest the large, arrow-shaped leaves several times throughout the season and add them to my compost heaps. Propagate from seed or division.

Lastly, the sinister Dracunculus vulgaris

(Dragon Arum) is the ultimate

extreme plant reaching

three to five feet tall.

A snake-skin patterned,

thick stem emerges from the soil

in spring with sickle-shaped

dragon’s claw foliage.

In early summer, a striking upward

thrusting spathe surrounds

an 18-inch spadix which mimics

both the color and smell of

rotting meat. The odor attracts

the flies that are its pollinators and luckily,

lasts only a day. The inflorescence persists

for almost a week. Need I say that proper siting

of this plant is essential. Hardy in zones 5-9, dragon arum prefers moist conditions in sun or bright shade. Propagate fresh seeds or divide in autumn.

By selecting a variety of different plants for your garden, you can attain both interest and drama, no matter what the weather brings. Consider planting a few moisture-loving divas in large pots as well. Be sure they have good drainage and  a thick top-dressing of mulch to help maintain moisture. And then, let it rain, let it rain, let it rain.

Printed in the Upstate Gardeners’ Journal, May-June 2010

© 2017 Gardens By Colleen. All rights reserved.