On Second Thought - Why I'm Ripping Out my English Marigolds

A December cold front with overnight lows in the 20s has blasted these English Marigold (Calendula officinalis) blooms, but the real peril here are the leafhoppers that are far too small to see in this picture.

Yes, dear reader, it was only 8 days ago that I was singing the praises of English Marigolds (Calendula officinalis) for their colorful early winter blooms and their potential as a sort of cover crop for flower beds.

And then, as they say in the U.K., it all went pear-shaped.

(Love the expression, but more prosaically, let's just say that I felt the experiment had run its course and was not a roaring success.)

What went wrong?

In a word: Leafhoppers!

In two words: Leafhoppers, argh!

I tend not to spray pesticides in the garden. Mostly I adhere to a survival of the fittest rule and if a plant can't take care of itself, I'm not going to coddle it along.

Well, I had forgotten just how susceptible the English marigolds are to leafhoppers. These insects are not terribly obvious until you brush against a plant and a little cloud of light green insects goes hopping off onto neighboring plants, only to quickly jump back to the Marigolds when your back is turned.

Leafhoppers suck the sap of vascular plants. In other words, they'll gradually weaken and then kill the host plant as their numbers increase. According to the Illinois Natural History Survey (INHS), leafhoppers do have many natural predators, but those predators do not seem able to keep the leafhoppers under control in my garden on this particular English Marigold crop. In fact, I now remember how I had to pull most of the English Marigold crop in mid-summer due to a leafhopper infestation (plus the fact that the Marigolds were baking in the heat and humidity of July and August).

I believe that English Marigolds must be particularly susceptible to leafhopper infestations, because I cannot recall having problems with them on any other plants this past year, except for the zinnias, which only became infested as they were already declining and reaching the end of their life cycle.

Now part of me, wanting to be a super eco-friendly gardener, supposes that it might be best to leave the English Marigolds. After all, the Marigolds do attract some bees and presumably the predatory wasps, spiders and birds that INHS says feed on leafhoppers would prefer to have a robust prey population.

Well, that may be the case, but I've never seen any birds browsing the marigolds for leafhoppers. Perhaps there are different birds that eat different leafhoppers elsewhere, since INHS says there are an estimated 100,000 species of leafhoppers around the world.

And besides, one major problem is that I don't want to provide an environment for the leafhoppers to breed and flourish. While my gardenia or my camellias for instance may not naturally support loads of leafhoppers, when the Marigolds foster massive populations, I think some of the little critters hop onto other nearby plants and do some damage there.

In any case, once the leafhopper population builds sufficiently on the Marigolds, many of the younger Calendula plants are overwhelmed early in their lifecycle, staying stunted and small, growing yellow and dying before they can flower, which sort of defeats the purpose of growing them as a cover crop.

So, gardening is a learning process and I'm certainly not above admitting my mistakes. (Mea culpa!) Even this late in 2012 I'm still learning and still making mistakes! And that's why at this point, I disavow the post I made just a week ago singing the praises of English Marigolds and revert to my earlier position that English Marigolds are more trouble than they are worth.

Now French Marigolds on the other hand, I endorse without reservations! :)  (But obviously I've been wrong before and may some day have to eat my words on this recommendation too!)

PS - What would you have done? Would you have sprayed? Pulled the plants like I did? Let events run their natural course?

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Winter English Marigolds - A Potential Cover Crop for Flowerbeds?

Self-sown English Marigolds (Calendula officinalis) in the December garden. These plants have survived temps in the mid-20s and are pumping out flowers, feeding bees and blocking weeds. The flowers last much longer than the 1st generation of English Marigold flowers did back in May and June.

Earlier in the year, I disparaged English Marigolds (Calendula officinalis) for their short-lived flowers. Many of the flowers seemed to live no more than a day before going through various (to my eyes) unattractive stages of decrepitude.

Well, as often happens in the garden, time provides some new perspectives.

The English marigolds self sowed - no big surprise given the vast numbers of seeds they shed. And since they came up this autumn, they have actually looked much nicer than the spring-sown plants.

I'm starting to think that English marigolds should really be planted as a fall crop in Tennessee. While there may not be as many flowers as in the spring, the flowers last much longer, the foliage looks more healthy and they don't even seem to want to form as many seedheads, which makes it much easier to keep up on deadheading them.

In fact, I'm going to go a little further and propose a somewhat radical notion: Maybe English Marigolds could be a fall cover crop for gardeners like myself who like to grow annual flowers. Since I don't mulch my beds heavily, I've got quite a few weeds (clover, etc.) coming up in the flower beds, but where English Marigold is thriving, there's nary a weed in sight.

I've also been super impressed with the Marigolds' cold hardiness. We're having a nice warm spell at the moment (highs in the 70s, lows in the 50s), but we had a number of nights with temperatures in the mid-20s in November and the English marigolds did not really seem fazed at all. Individual flower stalks sometimes seemed to get frozen, but the mass of Marigolds clustered together and the unopened buds seemed to come through those temperatures just fine.

I'm curious to see just how cold it has to get to kill these Marigolds. Teens? Single digits?

(The French Marigolds - Tagetes patula - are much more sensitive to cold. Those beautiful drifts of orange and yellow from late October, they are now just brown skeletons. But I actually like the nodding seedpods. And I've discovered that if you brush the seedpods with your foot (or hand) you'll release volleys of arrow-like seeds. It's a little painful if some of them lodge in your ankle!)

Now I don't have too much experience with cover crops, but I assume that when it's time to plant perennials or spring annuals, I can just cut down the Marigolds a couple of weeks beforehand and turn them into the soil.

What do you think of that idea? Crazy? Or worthy of consideration?

Meanwhile, I'm enjoying having flowers blooming in early December. And the bees seem to like having flowers around too!

December 3rd, 2012 - Bee on English Marigold (Calendula officinalis)

Update (12/11/2012) - After discovering a leafhopper infestation, I have changed my mind on the merits of English Marigolds, begun ripping out the existing plants and returned to my previous belief that the plants are more trouble than they are worth on multiple levels. Gardening, like life, is a nearly continuous learning process in which mistakes are often the best teachers as long as we are humble enough to recognize our errors and seek to do better next season. See what other positions I revise/reverse with a free email subscription.

Shots in the Garden! (June 21, 2012)

Sorry for the posting hiatus. I was traveling on business for about a week and the blog (and garden) were neglected while I was away. Fortunately, my wife was kind enough to do a bit of watering in my absence, plus we apparently had a couple of storms that may have helped keep the garden in bloom.

Without further ado, here are a few shots from my garden on the day of the summer equinox, 2012:


I have mixed feelings on Calendula officinalis (English Marigold). On the one hand, they attract bees and butterflies...

On the other hand, they tend to look kind of ratty, especially now that the summertime heat has kicked in. The flowers don't last long and they go through various stages of post-flower decrepitude so that there are typically many more obviously and visibly dead flowers on a plant than live blooming ones. And these post-flowering seedheads aren't attractive (like coneflowers) or inconspicuous (like cosmos) and they don't even seem to attract birds (like cosmos does). The overall effect is not shall we say aesthetically pleasing...

And yet, there are the interesting butterflies (or moths?)...

I planted an awful lot of Calendula officinalis this year, so deadheading is an arduous and unwelcome task. (I don't mind various gardening chores, but I'm not into deadheading.) Despite its ability to cover a lot of ground and provide weeks of flowering, I'm not planning on sowing English Marigolds again next year, for the reasons cited above. But in the future, I could see growing a small patch of them for the bees and butterflies.

Now on to the Sweet Alyssum. We planted a lot of it this year, both from seed and nursery starts. Most of it has languished or died, but some of the white ones have really taken off, growing big and bushy. Exhibit A:

Some of the alyssum is planted near the native trumpet honeysuckle. One of those honeysuckles (Alabama Crimson) is growing well, but has not flowered at all yet. The other plant (Blanche Sandman) is smaller, but already flowered weeks ago and has now grown and begun opening a second flush of flowers. Exciting!! Haven't seen any hummingbirds yet, but I'm hoping that as the honeysuckles get bigger, the birds will discover them. Here Blanche is ready for her close-up:

Finally, here's a close-up look at the 'David' variety of Phlox paniculata, a.k.a. garden phlox. Remember the buds from a couple of weeks ago? Well, many of those have burst in bloom now! According to Missouri Botanical Garden, this plant likes full sun, is hardy from zones 3-8 and can bloom from July to September. Garden phloxes have a reputation for being susceptible to powdery mildew, but David is apparently relatively resistant. The flowers have a light, sweet fragrance, but you have to practically bury your nose in the petals to smell it. Still, I don't mind getting up close to this...

But let's take a step back to give you an idea of the strong, upright form that the plant takes. We started with three Phlox plants last year. All three came back, but this one actually multiplied into four individual plants, or at least four stalks. According to the University of Minnesota Extension service, Phlox paniculata needs to be divided every two to four years if it is growing well. Being a relative newcomer to gardening, I've actually never tried dividing any plant before, but I'll probably give it a shot with the phlox next spring...

Shots in the Garden! (May 20-26, 2012)

Daylily (Hemerocallis), not sure of the variety because we inherited these dayliles when we moved in.

Busy bee at work gathering pollen from Cosmos flower

I believe this is a type of coneflower (Echinacea). I don't remember ordering it, but I think it might have grown from a bonus pack of seeds we sowed last year.

Russian Sage (Perovskia atriplicifolia) and bee.

I like the way that Zinnia buds look just before they open.

The front border is filled with bright and cheerful English Marigolds (Calendula officinalis, a.k.a. Pot Marigolds)

Pole bean seedlings (Phaseolus vulgaris, Spanish Musica variety) getting off to a strong and inspiring start.