Invasive Plants: Loved or Loathed

Invasive plants come in two categories; they are either welcomes or met with rage.  The loved ones first:  Forget-me-nots, Celandine poppy, Creeping Charlie, Scilla siberica.  The loathed: Star of Bethlehem. 

The loved ones are always well-received.  No matter how much territory they overrun, no one complains.  It’s impossible to forget a forget-me-not.  It shows up in April in the most beautiful shade of blue.  After blooming you can ignore them.  No attention is required; they advance wherever they like.  

Forget-me-not

Mine is a migrant from Marian Faux’s garden next door.  There are several varieties; ours is Myosotis scorpiodes, the true forget-me-not.  Our shared garden is awash with them, started by Marian against her house, and then marching over the years across property lines and into our shared garden.  There is no happier sight this time of year than that perfect blue found nowhere else.  We continue to ignore its’ official listing as an invasive.

 

Celandine poppy (Stylophorum diphyllum), a brilliant yellow, is native here in the Northeast.  I brought one with me from the Catskills garden and it has multiplied.  Its’ natural habitat is moist forest over calcareous rock but it  has agreeably spread out in a dark, well-watered corner of my garden. 

Celandine poppy

 

As for Creeping Charlie, all you will find in the literature is directions for getting rid of it.  Here it has colonized in the lawn where it is cut whenever the grass is cut.  It flowers in spring along with the scillas, followed by tidy green rosettes at its’ base.  Growing lower than the mower blades, it escapes all but the first cut.  My so-called lawn is really a collection of small-leaf green plants, all treated equally. No water, no fertilizer, no weeding.  Just a weekly mowing.  

 

Which brings me to the scillas, growing through the grass.  Scilla siberica was here when I moved in 11 years ago, at the very back of what was to become a garden.  No matter how much disruption, digging, re-digging, planting, brick-laying … it keeps returning. 

Scilla siberica

Star of Bethlehem (SB) on the other hand is greeted with groans, followed by vengeance. It starts out as pretty tufts of green followed by beautifully starry white flowers.  It dies back to nothingness, leaving gaps when it is too late to fill them.  Anything you might plant nearby in the expectation it will beat out the invader disappears in its path.  SB is relentless, spreading like wildfire, conquering everything in its way.  My advice to you?  As soon as the first clump appears remove it with ruthless efficiency, leaving no bulblet behind.  Here on Livingston Street, at great expense, the plan to eradicate it is finally underway. 

 

Unlike the persistent invasives, most herbaceous plants do not last forever.  Periodically, when you are in the mood, they should be lifted, divided, and replanted.  You will know the right time by observation; they just seem to dwindle.  This season stachys, astilbe, shasta daisies, iris are among those needing attention.  Some defy the odds, growing taller and wider each year -- hosta, cimicifuga, bleeding heart, peonies.  A few will surprise you.  My favorite and sole tulip Spring Green, supposedly only good for a year or so, keeps repeating.  

 

Spring green tulip

My neighbor, best garden friend and co-conspirator Marian Faux (first parent of the forget-me-nots) and I share a garden in which we plot to outwit partial shade and black walnut competition. This semi-sunny (often shady) border looks better each year, even though old favorites -- baptisia, peonies -- mysteriously disappear.  We attribute all losses (fairly or not) to the presence of nearby black walnuts, but we press on regardless.  

 

The pleasures of gardening with a like-minded friend are immeasurable.  Marian is a much more meticulous planner than I, with a better sense of what is right, possible, and fitting.  She pays close attention, while I am more of the crap-shoot school: roll the dice and there’s a chance you’ll win.     

 

Up until last year I kept a detailed map of the all the beds and borders, updating it annually and marking the changes.  I neglected this in 2022 and am faced now with the appearance of plants I don’t recognize and have clearly forgotten.  This is when Apps become indispensable.  I use a plant identifier and a weed identifier in tandem to jog my memory and to save me from eliminating something important. Satisfaction is guaranteed, but pointing your phone at something and receiving an instantaneous ID does nothing to train your memory or sharpen your observations.  Fair warning.

Getting Through March

 

By this time of year the gardener is usually able to report a noticeable change in the garden, but often the change is in the soul of the gardener and not the garden itself.  After a mild day or two we convince ourselves that it is the beginning of the new gardening year.  In Manhattan, a few weeks earlier than in Rhinebeck, daffodils will soon be poking their noses through the soil of street-side tree pits, cozying up to the warmth coming from the pavement.  

 

If you are dreaming of a cottage in the country with a garden and you wish to be disabused of the idea, now is the time to go house hunting.  After the snow melts a March walk through a garden can be sobering.  Rhododendrons are still shrouded in burlap.  Small piles of debris are everywhere.  Anything cut and left on the ground can be cleared away, but most of the larger material is still frozen.  Water has pooled and iced in low-lying areas.  Pots the owner didn’t get around to emptying and storing in September are still there, likely frozen and cracked.  

 

April 1 is the real start of the gardening year, and March merely the wind-up.  With all its climatic vagaries, March does manage to offer one definitive idea: Winter is over.  If you walk in the woods you will soon hear the spring peepers.  Farmers say that after they have been heard three nights in a row, spring is here to stay.

 

To help you through the winter, if you have an empty corner or a small wooded swath, consider the Snowdrop, Galanthus nivalis.  Garden writers love them, because it provides material when there is nothing else to write about.  Snowdrops give you something to look for when all else is still dormant, and leaves you free of worry about late frosts.  They are among the toughest of plants and if laid low by a late winter storm, will bounce right back.  

 

If you have been wise enough to plant snowdrops, and are on your muddy knees admiring your handiwork at eye level where they can best be seen, you will be happy to know that you can expand your crop by dividing as soon as the soil warms up enough to work, even though the snowdrops are in full bloom.  The conventional wisdom is that bulbs can be transplanted only when dormant, but that is not the case here.  If you wait until autumn there will be no trace of them above ground, and you will have forgotten where they were planted.  

 

The main danger to your flower borders in the winter months is the ground’s alternate freezing and thawing.  This does not happen where there is a guaranteed blanket of snow all winter, but in our more temperate areas you will often see plants heaved out of the ground by alternate freezing and thawing.  If you see this in your garden make notes to prevent it next year by heavy winter mulching.  Almost any mulch will do – straw, salt hay, evergreen boughs, compost or buckwheat hulls are all fine.  Just make sure to wait until the ground freezes before laying mulch.

 

March is the month when I review my notes from the fall and remind myself of successes and failures.  If a new plant has not performed to my expectations, I will give it another year or two to take hold.  A poor freshman performance should not be a death sentence. I, however, find it difficult to follow my own advice, wavering between a plant that just needs a little more time, and one that never should have been acquired in the first place.

 

If spring is not coming soon enough for you, and snowdrops fail to cheer you, visit the annual New York Botanical Garden Orchid Show, blooming in the Bronx at 2900 Southern Boulevard, until April 23rd.  It will help you get through these weeks until spring really arrives.