By the time gardeners knew that purple loosestrife planted in
gardens would end up posing a danger to our region's natural
wetlands, many of us had already fallen in love with the tall,
magenta-pink flower spikes of that easy-to-grow, long-blooming
perennial.
So, what's a gardener to do?
Luckily, there are some wonderful native plants that offer both
looks and performance that are just as good, maybe better.
Several years ago I replaced my own patch of purple loosestrife
with queen-of-the-prairie (Filipendula rubra), and I love it. The
bloom stalks look like big sticks topped with huge puffs of pink
cotton candy. Like purple loosestrife, queen-of-the-prairie grows
best in moist soil and blooms for weeks. The plants stand at least
4 feet tall, often more.
What other native plants make good substitutes for purple
loosestrife, an invader from Europe? Swamp milkweed (Asclepias
incarnata), with large, dusty-pink flower clusters on plants up to
4 feet tall, is a good bet. So is prairie blazing star (Liatris
pycnostachya). Its densely-packed, rose-purple flower spikes are a
magnet for butterflies.
All three native substitutes for purple loosestrife are hardy
throughout the Midwest.
When it comes to the plants we choose for our gardens, the
debate over natives versus imports sometimes gets emotional. Some
people are passionate about planting only natives, fearing that
aggressive imports will crowd out our native flora.
Still, I've yet to hear anyone pushing for ripping out hostas
and peonies, neither one of which we North Americans can claim as
our own. The trick is to discover which of the imports are destined
to become aggressive invaders and find good substitutes for
them.
Fortunately, finding the substitutes just became easier, thanks
to C. Colston Burrell's "Native Alternatives to Invasive Plants"
(Brooklyn Botanic Garden, 2006, $9.95). In the back of the book,
you'll find a list of troublesome garden and landscape plants and
the states where each one is considered invasive.
