Growing Concerns 573: Iris not blooming?

Early Summer!

When plants stop performing give them a sabbatical


Dear Janet,

I have standard, everyday iris in  sun all day. They do not bloom. The soil is hard clay but other plants, even hybrid iris, grow and bloom there. I have transplanted them, with the top of the root exposed per book instructions, but still they don't bloom. They do put out good new growth. At one time I had them mulched with cypress, then removed that after reading iris don't like to be covered. Still no blooms. They're deer proof so I want to grow them. Any ideas before I remove them to the trash?


Dear M.R.,

Give one to a friend who has never grown iris. If the plant doesn't bloom there, then compost them all.

Every year I hear from people with iris or other long-term garden inhabitants that stop blooming and refuse to start again even though all the conditions seem right. It's one reason I think that the best gardeners are those who know how to let go. 

We can track main factors, such as hours of sun, that the soil drains of excess water within 12 hours of being saturated, or whether primary nutrient levels in the soil are within established norms. Yet we usually don't know what the micronutrient levels or, more importantly, how they affect a given plant. We don't know about changes in our garden's microfauna -- the billions of tiny living things that inhabit the soil, releasing and creating nutrients, loosening and mixing soil and interacting with roots. Very few of us track hourly temperature and wind and those who do probably don't do detailed analyses of that data to identify trends.

Yet all these things and more affect our plants. There are so many variables and combinations that we can't ever know it all. We should give it our best try but be ready to smile and say, "I give! I'll stop trying to grow that, at least for a while."

Woody plants have evolved to persist in one spot for decades but even the longest-lived herbaceous plants have more fleeting lives. A field may sport blackeyed Susan or some other wildflower for centuries, but not always in the same configuration. Conditions in a particular spot change. Diseases and pests of the plant increase in number until the perennial ages and thins. Plants of other species seed themselves or creep into the gaps and the first perennial yields its place to a newcomer. Yet the ousted species' presence continues via seedlings or runners that take hold at some distance from their parent.

In our gardens we keep perennials too long in the same place. We also miss subtle signs of change, things we might notice if we took each plant's photo every year at a set time and examined those images as a sequence. Since we don't do this we overlook gradual deterioration, noting only major changes such as total cessation of flowering.

The smart thing may be to give up on a species. This doesn't mean losing an heirloom or special plant, since you can simply give it to a friend for safekeeping. Better yet, increase its chances of  survival by splitting it among several friends. Ask them to please grow the special plant for at least five years or to let you know when they are going to stop growing it so you can reclaim pieces. You may see your plants take on new luster in a new site and please new people.

Meanwhile, you can try something different. With thousands of types of ornamental plants to choose from, there must be something else you will enjoy, such as something from the genus Helleborus (Lenten roses), Ranunculus (buttercups), Amsonia (bluestar) or Euphorbia (spurge) that are not favored by deer.

Short reports

Speaking of independence day:

How about freedom from garden work?

S.K. wrote, "NOW JUST STOP IT!  I read your article the other day about moving plants all summer long. It's just a good thing my husband didn't see it!!!"

"Give me a break -- I've planted, moved, fertilized for him. I'm deadheading still -- that's enough."


"Plus did I mention weeding?  Although it is better this year because he's mulched more and used that Preen stuff."

"It's not that I don't appreciate how the gardens look and the talent it takes to put it together. But the bugs, the dirt, the sore muscles, blisters -- holy cow."

"How about a green thumbs up for the drones who don't know one plant from another but are coupled with gardeners who do make it beautiful, with the labor of loved ones."

Well said, S.K. Forget I ever wrote that. Take a holiday. Enjoy the flowers!


Green thumbs up

to creative weeding of all kinds. As an example, R.V. was faced with a plague of maple seedlings. So R.V. invited the neighbors to a garden party. At the end of the enjoyable afternoon, R.V. closed the gate and demanded as exit toll from each guest, 20 or more maple seedlings!


Green thumbs down

to complaining about "too." Sure, it was too wet, too cool, too gray or too variable this spring for this plant or that. Yet those same conditions favored hemlocks, foxglove and foxtail lily while giving drought stressed, see-through silver maples and chlorotic oaks a chance to recover.

 Originally published 7/3/04