(rosemary and gardenia failures)




A reader, in telling me how much he enjoyed reading this “gardener’s notebook,” went on to say that he especially liked – perhaps he said “found interesting” – my failures. Well, here you are Alan: Looks like I’ve done in another rosemary plant. I went to water it and was presented with leaves that were a bit more needle-like than normal rosemary leaves, and drier. I soon realized I’d killed another rosemary plant.

Except for periodically dying, rosemaries generally have been ideal herbal houseplants for me. Each leaf packs a lot of flavor, so it’s a plant you can actually use freely in cooking without decimating it. It’s also decorative as well as culinary, whether grown as a sprawling bush or — my choice – as a miniature tree. And it tolerates the dry, low-light conditions of heated homes in winter.

This last point, I think, has been responsible for my “rosemary death syndrome.” Those narrow, waxy leaves tolerate dry air, but the plant as a whole, my guess, needs plenty of water. Rosemary is not difficult to root from cuttings, so I’ve always had plenty of new plants to replace those I lost; my tack with current replacements is to make sure the soil in their pots is constantly moist. Already I’m amazed at how thirsty these plants really are.

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Gardenias are not as easy to root from cuttings as are rosemary plants, so the gardenia I lost a couple of months ago did not have a replacement waiting in the wings. Nonetheless, I’m taking up the challenge and am determined to grow gardenia successfully.

The more I mull over that loss, the more I believe water – or lack of water – was also the problem with the gardenia. As a matter of fact, too much water or too little water is probably the most common problem with growing plants generally. One of the challenges in growing gardenia is that it is particularly sensitive to either excess or insufficient water; I believe I erred in the direction of insufficiency.

Okay, so now I have purchased a new gardenia, a small plant in a 3” pot. My plan is to add some extra peat moss (to hold moisture) and some extra perlite (to drain off excess water) to the potting soil for this plant. I also plan to water more frequently – that perlite will help any excess water run down and out of the pot.

And then, just to make sure the plant doesn’t dry out, I’m going to hook up an automatic, capillary watering contraption that’s been sitting on a shelf in my garage for years. This contraption is basically a porous, hollow spike, the pointed end of which gets pushed into the soil while its opposite, open end fits to a plastic tube the end of which sits in a jar of water. As the soil dries out, it sucks moisture out of the porous spike which, in turn, draws it in from the reservoir via the plastic tube. The whole setup isn’t particularly attractive, but I’m growing gardenia mostly for the fragrance of its blossoms, which can make you giddy whether they’re on the plant or floating in a bowl of water.

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That dead gardenia did present an opportunity for another visit to Logee’s Greenhouses in Danielson, Connecticut. Why go all the way to Logee’s to replace a relatively common plant like a gardenia? Because they offer about a dozen varieties of gardenia, as well as quite a few jasmine varieties, oodles of begonias, and all sorts of other exotic and wondrous houseplants.

I opted for “Four Seasons” gardenia, which is said to bloom sporadically throughout the year. Each blossom packs a whollop of aroma so a constant supply of just a few blossoms is all I need.

[mandevilla, cottony cushion scale]




Mandevilla Crimson, the vine about which I wrote and raved a couple of months ago, has become a horticultural Dr. Jeckyll and Mr. Hyde. Can this plant really be the same one that was compact and drenched, nonstop, in crimson, flowering funnels such a short while ago?

Winter light – that is, the lack of light — has made all the difference. Neither a flower nor the inklings of a flower bud are to be seen anywhere on the plant. And from the once compact mass of foliage has sprung 3 and 4 foot long shoots that are reaching out and grabbing onto a nearby rosemary plant, a lamp, anything around which they can twine. Even the leaves have undergone a transformation, although not nearly as dramatic. They’re merely smaller.

Strengthening sun should, hopefully, bring my mandevilla back to its Dr. Jeckyll persona. But what to do about all those willowy shoots? I’d like to cut them back, but according to “manufacturers” directions: “These shoots in the spring and summer will provide the flower buds for the next season flowers so do not remove or cut back hard in the spring.” Hmmmm. The manufacturer also states, in apparent contradisciton, that the vine flowers “on every third leaf pair, measured from the base or from the previous flower.” So new growth can give rise to new flowers.

My plan is to let those long shoots enjoy themselves and keep growing and building up the plant’s energy. Then, when the sun is brighter, perhaps the first day of spring, I’ll lop them back and hope for flowers from “every third leaf pair.”

I’m not soured on mandevilla crimson, in spite of its dual personality. As compared with past mandevillas, this one’s leaves kept greener in winter and the plant, during the growing season, is more florific and compact.

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Now that I’m looking more closely at my mandevilla, I do see another of its Mr. Hyde side: cottony cushion scale. Sure, it sounds sort of homey and looks soft and white. But it’s bad news.

Lurking within those soft, cottony exteriors are insects, ones who have inserted their proboscises into the stems, typically at the junctures where leaves meet stems. Through those proboscises, scale insects are sucking plant sap, the lifeblood of plants. Plants are weakened sometimes to the point of death. To make matters worse, the insects secrete a sticky honeydew which drips all over the place and then, to make matters even worse, becomes colonized by a fungus that makes the honeydew turn sooty black. To make matters worse still, that sooty covering over the leaves cuts down light and, hence, photosynthesis, which is how plants make their food. And as a final badness, that scale can spread to other plants.

Now I’m tempted to toss mandevilla Crimson into my compost pile. I won’t, though. I’ll start organically, attacking the scale mano-a-mano, rubbing it off by hand. Then, armed with a cotton swab dipped in alcohol, I’ll snuff out more of them. Finally, I may take the plant outside on some warmish day and spray it either with “light horticultural oil” or “insecticidal soap,” neither of which presents an environmental or health hazard. Most important is to keep up with these treatments because young crawlers and eggs continue to develop and lack that obvious, cottony baggage.

For starters, I am going to go ahead and lop back all those willowy stems. That will make the buggers easier to find and present less stem – and, hence, less buggers – to deal with in the first place.

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Mandevilla crimson is not the first of my plants to ever get cottony cushion scale. I’ve had it on jasmine plants and the related armored scales, which look like brown pimples, have attacked my staghorn fern and citrus plants.

Midwinter is when scale insects start to gain steam, and then the race begins, the insects trying to multiply as I try to keep the plants healthy and minimize that sticky goo all over the place. Once the weather warms enough to put the plants outdoors, these insects pretty much disappear. Perhaps they don’t like the climate outdoors; perhaps plant sap isn’t as tasty to them come spring; perhaps natural predators go to work. Perhaps it’s a bit of all these things. What I do know is that the scale insects are no longer a problem – until next year at this time.