Hill Gardens of Maine - Deadheading...The KEY To Late Summer Color

Click on "Teddy" for Fred's Amazing Journey Back In Time

Answers to your gardening questions

Article Archives

Complimentary Copy of "Keys to the Garden Gate"

Five-part article series on flower-drying starts here

Eight-part article series on vegetable gardening starts here

Asian Lily Beetles

A new scourge in New England ornamental and veggie gardens.

Japanese Beetles

They can be controlled...but not the way you think.

An effective Deer Fence!

Only three feet tall...and no deer has ever jumped over it!

That Last Ounce of Summer Color
by Fred Davis, MG, Hill Gardens of Maine (To view other articles, click Archives)

Welcome through Fred's Garden Gate! "What?! Foxgloves that bloom twice in one season? What’s that you say…delphiniums, too? And lupines? Even my perennial geraniums? Why…I never heard of such a thing!"

That’s right, McGee! There really is a flower garden Santa Claus! More than a few perennials – and quite a number of annuals, too – will either flower a second time during our brief growing season, or may even bloom almost continuously. How? You may have heard it a dozen times from books, articles and on TV garden shows. This time, however, let’s help it sink in deeply and permanently.

First, answer a couple of quick questions. Why does a plant produce flowers, pollen and fragrance, anyway? Answer: for no other reason than to encourage pollination and, ultimately, to produce seeds (or fruit, nuts, berries) and therefore, to reproduce itself! It has only one, single, urgent requirement in it's brief life: to have babies...to make more of itself. No...it's not there to be pretty and provide humans with beauty and a proof in the existence of deity; it's not there to provide bees with honey and pollen—though most flowering plants do that very well. Seeds! Plants have got to make seeds!

Well now, suppose the plant is denied fulfillment of that one, urgent, driving and inflexible duty of reproducing itself by seeds? Answer: it has no alternative – it MUST keep trying! And there is the solution—if you don’t allow seeds to mature on many flowering plants, they have a duty to at least attempt to make more…ergo: more flowers! BUT…once one tiny seed or seed pod actually matures to the point of sprouting on its own, the plant’s duty—destiny, if you like—is fulfilled. It’s done. That’s about all the flowers you’ll squeeze out of it. OK, so much for the technical stuff. Now let’s get to the nitty-gritty.

DEADHEADING! So now let’s get out there and whack off all those useless seed heads and pods before they begin to mature. Remember: If you don't let it have babies...it has to keep trying!

First the FOXGLOVES (digitalis). Remember that foxgloves are a biennial – that means they normally grow for one season, winter over, come up the next spring, bloom and then die – so you really want to squeeze as much color out of them as you can. As each flower along the stem fades and drops, remove the seed pods. When all that’s left are a few pitiful flowers out on the very tip, cut the stem down to the first obvious lateral (usually down to about 12- to 18-inches) and feed with a high middle number (phosphorus – for flowers). Consider allowing the seed pods from this second-generation of flowers to mature and fall so there’ll be some seedlings for the following spring.

Now let’s move on to the DELPHINIUMS. While delphiniums are actually a full perennial (returning year-after-year, with care and maintenance), you’ll do almost exactly the same thing for them. This tall perennial isn’t going to reward your diligence with an abundant display of tall and magnificent spikes, but there’ll be enough color to fill in some of those late-summer color-gaps. Don’t bother to save the second-generation seeds; likely as not they won’t germinate in average Northern New England garden soil…at least not without heroics.

Next comes LUPINE. This showy, eye-catching, late-spring/early summer perennial would be happy to deliver a second series of equally-stunning color during July – and even into August! It’s the same ‘ol story: get that first batch of seed pods off long before they mature. Allow second-growth seeds to remain on the plant if you’d like a few seedlings to emerge next spring.

There are a few others which will respond to early deadheading. Some noteworthy varieties: columbine; some campanulas; shastas or shasta-like daisies; some of the coreopsis; monarda (beebalm); I’ve even seen veronica (speedwell) continue to bloom after nearly-spent flower spikes are removed.

Don’t limit your deadheading to perennials only. Most flowering annuals, too, will respond favorably to timely removal of spent flowers and early signs of seeds. Even the ones that are touted to be self-deadheading.

While a number of popular perennials will not rebloom after deadheading, they should, nonetheless be ‘cleaned up’ just for appearances sake. Among them: achillea (yarrow); alchemilla (lady’s mantle); anemone; most asters; daylilies; dianthus; gypsophila (baby’s breath); hosta; liatris (gayfeather); asiatic and oriental lilies; and others.

One final point: immediately after removal of spent flowers and immature seed heads or pods, a refreshing dose of high-phosphorus food should kick them right back into more— slightly-shorter—flower buds for continued color deep into summer—Miracle-Gro for annuals; granular ("steak ‘n potatoes") for perennials (I recommend the use of Miracle-Gro only for annuals; not for perennials).

So, if you’re sorely disappointed with the highly-noticeable color gaps in your late summer/early fall perennial flower beds while someone down the road still has magnificent color right up 'til frost, invest a few moments every morning, afternoon or evening strolling through your garden with a pail and pair of snips. Soon, neighbors and passersby will stop you on the street with the question: "How EVER do you get so much color in your garden this late in the season?!

Enjoy your late-summer garden!

Our Local Weather

Find your State and County Cooperative Extension Office

Which Maine Hardiness Zone Do I Live In? (.pdf)