Plants For Wet Soils

It’s true that April showers bring May flowers, but
they also bring wet compacted soils. I grew up in Nelson County between the Salt
River and the Rolling Fork River, which seemed to overflow their banks like clockwork.
Our home was far from any possible flooding danger, but I remember many who were
not so fortunate. Watching the rivers swell so quickly and take over the land
left me with a little fear and a lot of respect. But it also gave me a desire
to understand the result and how to use it to our advantage when gardening.

Soils that are naturally wet, temporarily flooded,
or heavily compacted have one thing in common: little or no soil oxygen. A living,
growing root system requires oxygen to function and survive, but there are plants,
especially native ones, that have adapted and will grow even in standing water.

Black gum & bald cypress trees

Two trees come immediately to mind that thrive
under wet or heavily compacted conditions. The first is our native black gum,
Nyssa sylvatica. This tall tree is relatively slow-growing but will obtain a
height of 50 feet or more. As with many species tolerant of wet soils, growth
will be accelerated if the soil is moist and dramatically reduced if the soil
is dry. The glossy, dark-green leaves of summer are hard to resist, but you
are in store for an even more stunning show in the fall of orange to scarlet
and sometimes almost purple. Unfortunately, this tree can be a little hard to
find because it is difficult to transplant. Look for plants that are small and
container-grown. If you luck upon a large balled and burlapped specimen, make
sure you ask if its roots were properly pruned in the nursery to ensure establishment
and survival when planted.

Bald cypress, Taxodium distichum, also a native
tree, is an extremely beautiful and adaptable tree. Many are reluctant to plant
it because of the cypress knees that develop when growing in standing water
or a consistently wet environment. These knees are not found when grown under
normal soil conditions, as I can attest to, because I have one growing in my
own back yard. I enjoy the soft green of summer, the rusty fall color in October,
and the stately form and reddish-brown bark and branches in winter.

Buttonbush & spicebush shrubs

Buttonbush, Cephalanthus occidentalis,
a native shrub, has glossy foliage that tends to emerge late but makes up for
it by hanging on late into the fall. One of the most beautiful plantings I have
seen is at Bernheim Arboretum, near Bardstown. The recently renovated King Fisher
Pond was previously almost hidden but now has a beautiful garden with species
suitable for wet sites around it. The most unusual characteristic of buttonbush
is the flower. The creamy white flowers are about an inch in diameter and are
more like a fluffy sphere than a button. They are subtle but beautiful and appear
in late June, continuing to flower until early September.

Spicebush, Lindera benzoin, is a native shrub
that prefers a slightly shady spot in which to grow. The flowers on this shrub
are yellow, but only the females bear the scarlet fruit as it is dioecious.
It is grown ultimately for its spicy aroma, which comes from all parts of the
plant when brushed, bruised, or broken. I am particularly fond of the yellow
fall color that glows from a dark shady spot in any garden.

Wildflower perennials

With perennials it seems there are even more
to choose from. The native swamp sunflower, Helianthus angustifolius,
and Joe-Pye weed, Eupatorium purpureum, are tall perennials and can reach
heights of 5 to 6 feet. When the soils are dry these perennials will grow to
only 4 to 5 feet tall.

The swamp sunflower is noted as being one of the
finest fall flowering plants for our area. Unfortunately, it seems retailers
concentrate on selling the traditional and overused "garden mum" or
chrysanthemum, instead of promoting more of the reliably hardy fall-blooming
perennials for the garden like swamp sunflower. This perennial spreads slowly
in the garden, forming small mass plantings, and should be trimmed back slightly
around the first of June. This will encourage denser, stronger growth to support
the abundance of golden-yellow flowers that appear in early fall.

Joe-Pye weed is almost famous. It seems everyone
recognizes this wildflower from the roadside as they travel around Kentucky
in late summer and early fall. The large purple flower, 12 to 15 inches in diameter,
can be even larger in fertile wet soil. It is actually made up of several flower
heads coming together to make a truly impressive show. Eupatorium maculatum
‘Gateway’ is one that resides in my own very dry alley garden. This form is
slightly smaller in habit with stems that are speckled purple and larger flowers
that, to my eye, appear more pink than purple.

So if you live in an area that has wet and heavily
compacted soil conditions, either due naturally or from an overflowing river
bank, there is hope for a beautiful garden. The water may rise and fall as the
rich river topsoil moves from one farm to the next, but the plants that survive
and prosper afford us an opportunity to garden beyond our wildest dreams.