Why won't my iris and peony bloom?

Ever notice how nurturing a garden is a lot like raising kids?  Like our children, we try to establish our plants, encouraging them to lay down roots, and flourish.  We organize their space and weed out the bad influences that threaten to take over their territory or rob from them of nutrients.  Kinda like a bully demanding lunch money.

As the garden matures, we make plenty of mistakes.  We choose the wrong companions for them at times.  We don't always make the effort to study their individual natures, and they wilt.  Instead of rooting out our own errors, we become baffled, and decide there must be something wrong with the plants.  At times we become discouraged or busy, and the garden suffers neglect.

Through all the daily triumphs and travails, we cobble together a relatively healthy, attractive garden space and pat ourselves on the back.  After years of hard work we've established an enviable plot of land that friends and neighbors admire, flush with plush plantings that we enjoy spending time with.  Our job here is done.  The plants have grown and can pretty much tend to themselves.  We, proud parents, are merely in maintenance mode.

But then things go wrong.  For me, it was the failure of my well-established peony to produce the abundance of blossoms it usually does.  And the bearded iris didn't bloom at all this year!  I'd diligently created space around these plantings, so they wouldn't get crowded out of the flowerbeds.  I'd divided the iris last year, sprinkling rhizomes around the yard so they could take off in many areas.  I'd even doused them with fertilizer in May, to ensure they'd have the proper nutrients to reach their maximum potential.  But my efforts, it seems, were in vain.

So what do we do when our "babies" fail to thrive?  If you're like me, the first thing we do is panic.  We doubt.  Then we let determination take over.  I hit the Internet running, and thumbed through my extensive library of garden manuals.  Here's what my research turned up:

When a peony doesn't bloom

Temperature:  Part of the problem is out of our control.  Peonies thrive in cooler zones Usually zones 3-7).  They need to have a certain amount of days in the off season that dip below 40 degrees in order to properly form buds.  If your winter was milder than usual, the peonies will suffer for it, and produce fewer blooms.  This was NOT the case in upstate New York this past winter, so I had to look elsewhere for the culprit.

Light:  Peonies like at least six hours of sun each day.  Knowing this when I planted my peony 15 years ago, I chose the sunniest spot in my yard.  Unfortunately my nearby Japanese maple, only as tall as the day lilies back then, has grown to 30 feet.  It literally steals some of the peony's sunshine.  So today I put in a call to my arborist to schedule a trim.

Plant depth:  Peonies don't like a lot of soil smothering their roots.  Of course I planted them shallowly, but over the years as I've added other plants and amended the area, I inadvertently covered the peony roots in additional soil.  This, I believe, is the main reason my plant is suffering.  What can I do?  Today I will gently scrape some of the soil from the area, but it's really too late to aid the peony this season.  After August 15, I can gently lift the plant out (starting to dig a full foot-and-a-half away so I don't slice any roots), and replant it so that it has only an inch of soil around its roots.   This is tricky because peonies don't love being moved.  I must be careful not to damage the roots or foliage.  And I'll amend the soil with dehydrated cow manure and sphagnum peat moss before I place the plant back in the area.

When bearded iris won't bloom

Tight quarters:  If bearded irises become overcrowded they won't blossom.  They need to be divided every three to four years.  I divided mine last spring, so I thought I would get full bloom this year.

Light and depth:  Like peonies, irises also won't bloom if they're planted too deep, or don't get enough sunlight.  When planting iris, make sure to simply lay them on the ground and cover over lightly with a half inch of garden soil.  You can even leave a thumb-sized rhizome protruding from the ground.  And they, too, require 6 hours of sunlight each day, so I suspect my yard is becoming too shady for them.

Too much of a good thing.  If irises get too much nitrogen from fertilizer, they'll be nice and green--at the expense of the blooms! Sprinkle a fertilizer no greater than 10-10-10 (which stands for the ratio of NPK values--nitrogen, phosphorus, and potassium--in soil.  These are the three main plant nutrients).

Now I must be patient.  My plants--like the kids and countless pets I've raised--do best when I allow them the time it takes to reach their full potential.