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Why Did My Plant Die?

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Archive
Here's the Vast and Cavernous Archive of Enquiry that the Doyenne has already answered. Good clean fun for the whole family.

This week's questions:

  • Sad Glads
  • Uncooperative Jasmine and Maple Ulcers
  • Relocating Glads and Iris
  • Non-Grass Lawn Substitute
  • Mock Orange Needs Tough Love
  • Yuck -- Powdery Mildew
  • Dandelion Invasion
  • Cecile Brunner Only Blooms Once!

    Sad Glads

    Dear Doyenne,
    My wife has been planting gladiolas each year in the garden in rows for cutting. This year they appear to have a blight or rust of some kind. The foilage look rusty and mottled and the flowers are also covered with transparent blotches and look damaged. They also wilt off before the last blooms open. The glads in other beds away from the garden seem fine. I used a pre-emergent weed inhibitor in the garden, could that affect the plants?

    Can you tell me what might be wrong with the glads? Will this malady affect the bulbs if they are replanted next year?(I live in Pennsylvania and store the bulbs in my cellar over winter.)

    Thank you,
    David

    David,
    Glads are subject to a number of different viruses. Sorry to say, the best thing to do is remove them and then toss them in the trash. The virus could have come in on the bulbs, or was already present in the soil. Plant something else in their place, certainly, but not more glads. Dahlias would be a good substitute. And while the pre-emergent you used probably had nothing to do with your problems, you might on the whole want to consider a more organic approach to weed control.

    Best, KL

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    *****

    Uncooperative Jasmine and Maple Ulcers

    Dear Doyenne,
    I am on a nice hill in the Seattle area (east side). I have 3 jasmine plants (2 are J. polyanthum) -- 2 last year's and one this year. This year's bloomed and is trying to have a few blossoms now, but the other two didn't bloom at all. How can I make them bloom and do they only bloom once per year?

    We have an ornamental maple which grows prolifically, 20ft tall growing in the open by the street. This year I noticed that on nearly EVERY leaf there were raised "warts" that in most cases eventually cover the leaf entirely. It is awful (actually frightening!) visually. Will it spread through the yard to other plants? What is it, what's the danger and what's the cure?

    Thank you,
    LJ

    LJ,
    First, let's talk jasmine:

    Jasminum polyanthum is very tender in the Northwest even though it's often sold at garden centers. It is root hardy, yes, but seldom puts on a big show of flowers because it blooms on old wood which is usually damaged in winter (and because it blooms on old wood, you should not be pruning it back). This is a plant that requires overnight lows of 35 to 55 to chill it and make it set bloom, which makes it superb for an unheated greenhouse, but not the year-round garden.

    If you want a jasmine that is hardy and blooms well all summer, look for Jasminum officinale, poet's jasmine, with fragrant white flowers. It can easily take zero degrees Farenheit and will quickly cover an arbor.

    It's hard to diagnose your maple sight unseen. The problems may range from parasitic wasp eggs (not really that much of a problem for the tree, just weird looking) to a nutrient deficiency that causes leaf warping. Given the fact that it has only happened this year, I'd vote for the former. Generally this won't happen often, as wasp populations fluctuate. Another possibility is damange from aphids that could have attacked the maple earlier this year. Either way, not much to be done but wait and see.

    Enjoy, KL

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    *****

    Relocating Glads and Iris

    Dear Doyenne,
    As the Queen of the 'relocating garden', I am hoping you can help me!

    I am knee-deep in iris and glads without a clue what to do with them. All are done blooming, and I dug them up and put them in every conceivable five gallon container and bucket I could lay hands on. When I ran out of pots, I temporarily 'planted' some iris along the edge of my manure pile, in the loose rich soil formed there, with a layer of old hay as mulch. I must have at least 100 iris plants, maybe 50 glads.

    I don't want to plant them here, as I am relocating, so need to store them somehow for a couple of months. Ideas?

    Thanks,
    Sue

    Sue,
    You're in luck! Both gladiolus and iris (yours sound like German bearded) can be easily stored for several months. Once the foliage has turned yellow on the glads, dig up the corms, shake off all the dirt, and store them in a container full of shredded newspaper, packing peanuts or some other dry medium. Keep the container in a dark, cool, dry place until replanting time.

    Slightly different treatment for the iris: divide the tubers into plump and healthy single sections (6" long) with a crown of leaves. Cut the leaves back to 2" from the tuber and then store as you would the glads. If you have too many iris sections, give them to friends! In your climate bearded iris can be planted anytime from December until April.

    Best, KL

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    *****

    Non-Grass Lawn Substitute

    Dear Doyenne,
    I recently started thinking about a lawn substitution for my very sunny backyard in Richmond, CA. It is a large sloping yard covered in disgusting and invasive weedy grass that I would desperately like to remove (when I have a spare year).

    I do not want a formal looking lawn but I would like something that can stand a little foot traffic (no kids or dogs), that is fairly drought tolerant and low maintenance. I have heard about mixtures of yarrow, clover and thyme that sound interesting but I'm wondering if you have any other ideas. Oh, and the soil sucks -- clay, rocky, etc.

    Thanks,
    Allison

    Allison,

    Well, given how awfully dry Richmond can be, I'd recommend Thymus minus, creeping thyme. Also Laurentia fluviatilis, blue star creeper, which will need watering until it's established. Same goes for Mazus reptans, a wonderful flowering groundcover that comes in blue or white. Then there's the very low creeping iceplant, Delosperma nubigenum. Finally, for large areas of ground that get very little foot traffic, there's good old creeping rosemary, or Helianthemum, the sun rose.

    Best of luck, KL

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    *****

    Mock Orange Needs Tough Love

    Dear Doyenne,
    I have a beautiful, gallopingly tall mock orange that's about 4 years old. I have mulched it, fed it with Miracle-Gro and it's in full, full sunlight. We're about 2,200-feet up on the Cumberland Plateau. I prune the plant minimally and it looks as healthy as one might wish; however in all this time and with all my care, this plant has produced exactly one blossom. What can I do to get blooms?

    Thanks,
    Connie

    Connie,
    Could be too much love! The genus, Philadelphus (mock orange) is adapted to growing in nutrient-poor soil. I recommend you stop feeding it and cut back on watering. A little benign neglect should give it the impetus to bloom.

    Best of luck, KL

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    *****

    Yuck -- Powdery Mildew

    Dear Doyenne,
    I live in Southern California in the San Fernando Valley, where it is quite hot and usually dry. I planted zinnias from seeds this year in an area that gets full sun in the morning, and shade after about 2 p.m.

    They were fine until they developed a white-powdery scum on the tops of the leaves and look quite bedraggled. I have never had problems with zinnias before. What's up?

    Thanks,
    La

    La,
    Welcome to powdery mildew. Zinnias get it. And sooner, usually, than later. You might try growing them in an area that gets even more sun than they get now, at least until 4:00 or 5:00 in the afternoon, then keep them well watered without getting any moisture on the leaves (read: drip irrigation, or just lay the hose at their feet). If the problem continues, use a sulphur-based fungicide (Safer, brand name, puts one out). One or two applications should dry up the mildew. Other option: more SoCal adapted plants.

    Best, Doy

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    *****

    Dandelion Invasion

    Dear Doyenne,
    My question revolves around trying to be environmentally conscious in caring for my lawn. I have dandelions that keep sprouting up in my lawn. Up until now I have refrained from using conventional products to try and get rid of them. I have merely removed them. Unfortunately they keep sprouting up with deeper and deeper roots and I keep having to gouge bigger and bigger holes in my lawn to get them out. Is there an environmentally benign or neutral product that you would recommend I use to inhibit their reappearance?

    Thank you,
    Ralph

    Ralph,
    The most environmentally benign way of dealing with dandelions is the way you're already doing it. Ideally, a healthy lawn will out-compete the weeds. Here's a suggestion: In fall, when the rains have begun, apply a dose of lime to your lawn (recommended dose is 5# per 100 square feet). If you haven't limed your lawn (ever) or in several years, you might begin with 10# per 100 square feet (this dosage will eliminate moss in your lawn, as well, so be forwarned) Then, aerate your lawn with a pitchfork or a hayfork by just stabbing away. Finally, apply a dose of fertilizer, e.g., Nature's Intent granulated fertilzer, which is completely organic. That should give your grass a head's up over any weeds.

    Best of luck, KL

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    *****

    Cecile Brunner Only Blooms Once!

    Dear Doyenne,
    I live about five miles inland in the California Monterey Bay area. A few years ago I saw a vigorous, established 'Cecile Brunner' climbing rose in full bloom and, like so many before me, fell in love. I eventually found one and planted it in a perfect spot at one corner of the house that receives all day sun. The plant blooms nicely once in the spring and then simply ceases to perform. It continues to generate profuse amounts of foliage throughout the summer, including many of the large, arching canes I am told generate the blooms. Because it grows so heartily, I do not fertilize it. Though I am pleased that has taken over one entire side of my deck, I am very disappointed that it refuses to produce even sporadic blooms after the initial spring show. Is this just the way 'Cecile' is, or is there a remedy?

    Thanks,
    J.B.

    J.B.,
    Sorry to say, it's the nature of the beast. 'Cecile' only blooms once in the spring. If you'd like an ever-blooming climing rose that is similar (though not exactly the same), try 'New Dawn', which blooms all season long.

    Best, KL

    Read a gardener's difference of opinion.

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