Welcome through Fred’s Garden Gate!
Readers of my gardening columns and visitors to the web site have asked for guidance in dealing with thoroughly overgrown perennial gardens.
“...invasive perennials have just taken over. I don't know what would be the best and most effective way
to [fix] this...” wrote one recent emailer. Let me now share one effective solution with you.
First, to do it right, you've got a lot of work ahead of you...involving a fair amount of time. Those invasives have probably spent years (if not decades) producing bazillions
of seeds that're now evenly distributed throughout the working depth of your garden topsoil (not to mention a thick mat of tangled roots, many of which have the ability to produce new plants from tiny whacked-off sections). Getting the plants out isn't the problem. Eliminating all those seeds—and equal numbers of bits and pieces of
Old-time gardeners have a saying that is at once succinct and absolutely true:
"One year seeds...seven years weeds." It applies to ornamentals, as well. Burn that little kernel deep into the
ol' memory bank. Here's what works fairly well for me:
Religiously and almost fanatically remove all of this seasons' spent flowers and seed-heads from
everything. At very least you can avoid the necessity of dealing with a crop of new seeds. Search out and remove any healthy and desirable plant that you want to salvage (at this point, don't worry about the season...just get them out) and carefully work the root system to evict anything you don't want to move into a new garden. I use a wheelbarrow full of water and, after shaking off as much soil from the now-cut-back plant as possible, that which remains gets dunked and thoroughly cleaned with a nozzled garden hose. Keep the
good guys....toss the scoundrels (or scatter them along the sides of a dreary and boring country road).
Re-plant or heal-in the now-sanitized good guys into a new temporary home...and get ready for the more difficult task ahead.
Remove everything—stem, crown and root system. The process will almost turn the whole place upside-down. That having been accomplished, your patch of ground will probably be a few inches lower than before. Rake it all out more or less smooth, scatter a thin layer of nitrogen-heavy fertilizer (or [shudder]
some "miracle" blue water), water it well...then go about your “real” life or day job. In a few days, the plot will look like an emerging lawn of freshly germinated invasive perennial seedlings. Wait for a dry, breezy day and go after that bed with an iron garden rake and totally disrupt those new little babies
(sorry) to a depth of an inch or two.
After a couple of those dry and breezy days, water it again....and wait. Another batch will sprout. Rake them down again.
Wait a few days...water...wait...rake. Again...and again until only a few pitiful little seedlings dare to show their faces. That entire process will likely take most of the season. Each time you rake them down, it comes close to counting as one year off the proverbial seven.
Now, about mid-Fall, scatter a healthy dose of granular fertilizer (I use 10-10-10) or an organic equivalent and cover that with a good,
honest 4 or 5 inches of clean topsoil (or contaminant-free compost like
Cycle-Gro if you can afford it; I do not like sewage sludge!) and re-build all the paths, borders, stepping stones, etc., etc. Be careful not to allow anything more than the top couple of inches of the old bed soil to be mixed with this new—presumably clean—upper layer. Scatter a layer of weed-seed-free wheat or oat straw over the entire patch of bare earth and walk away for the winter. Never use plain
ol' field hay, unless you want your new hard-won garden to look like a cow pasture!
After the thaw and last killing frost next spring, replant to your heart's desire. A finishing inch or two of clean mulch like shredded leaves or very fine, natural (unstained and untreated), shredded bark will dress it up, help conserve moisture and prevent any remaining undesirable seedlings from reaching
Most of it is done. The rest involves watching closely for the next couple of seasons for signs of unwanted remnants of the old garden...and graciously accepting kudos from neighbors and passersby. Then you can take your cup of tea and stroll through a beautiful restored garden in the glow of an early morning sunrise. How good is that?!
There's an entire
chapter on garden maintenance in Keys
to the Garden Gate! While
you're there, download the entire book...it's complimentary.