IN THE GARDEN: Visible "dirt" on plants nothing more than oak pollen

Oak pollen stuck to the leaves of this Mahonia looks like trouble but probably isn't. (Special to the Democrat-Gazette)
Oak pollen stuck to the leaves of this Mahonia looks like trouble but probably isn't. (Special to the Democrat-Gazette)

Q Attached are pictures of a camellia and a Mahonia holly. The plants have what looks like dirt on the older leaves. It will even rub off like dirt would. I have had tea scale in the past but that seems to be under control with treatment. The "dirt" problem is on all five of my camellia japonicas, in three different parts of my yard. I first noticed it last year and tried insecticidal soap with no real success. All the plants bloomed pretty well and are putting out clean new leaves. They have shed a lot but not much more than usual. I am not as worried about the Mahonia, which is next to one of the camellias, but the sad leaves on the camellias really bother me!

A The "dirt" is actually pollen, more than likely oak pollen that fell during the rainy weather and collected or got "glued" onto the leaves. It won't hurt the plants, and as you can see, the new foliage is coming on clean. I am surprised that some of our heavy rains haven't helped to clean the leaves a bit, but unless you want to wipe each leaf by hand, I don't think there is much you can do.

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Q This daisy has stunted growth at the base, and I'm wondering if it is diseased and should be pulled. There is another daisy in another part of the bed that looks fine. It was just planted last fall but we had a hard winter and lots of rain this spring. I am in Northwest Arkansas. Thank you for your help.

The disease asters yellow can cause damage like these stunted daisy leaves. (Special to the Democrat-Gazette)
The disease asters yellow can cause damage like these stunted daisy leaves. (Special to the Democrat-Gazette)

A I think your daisy has a disease called asters yellow. This is a systemic disease caused by a bacterium-like organism. The disease is often mistaken for herbicide damage because it distorts the host plant. (It is also possible it is herbicide damage, if you know someone has been spraying nearby with weed killers.) If no herbicides have been used, then I suspect the disease. In some plants infected with asters yellow, the leaves are stunted or twisted, which is happening here; when other plants are infected, their typically showy flowers stay green and grow extra petals. The disease usually won't kill the plant, but there is no cure for it either. I recommend removing the damaged plants so that insects don't feed on them and transfer it to something else.

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Q Our rose bushes are thick and lush and full of buds — that don't open. We cut the buds off several weeks ago after they failed to bloom and loads of new buds have grown back but still don't open.

Rosebuds that fail to open could be infested by insects, or weather might be delaying the blooms. (Special to the Democrat-Gazette)
Rosebuds that fail to open could be infested by insects, or weather might be delaying the blooms. (Special to the Democrat-Gazette)

A Is there a reason you cut the old buds off besides they just are not opening? Did they dry up and turn brown? I might consider sacrificing one bud and cutting it in half to see if there are insects inside. From the picture you sent, it appears healthy and happy. Maybe all the cool weather and rain just made them sluggish. Ignore them for a while and see what happens. You can also take a cutting with rose buds on it to your local county extension office for disease diagnostics.

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Q I have a large, old yaupon holly that is busting up a brick retaining wall. Repairing the wall properly will likely disturb about 40% of the 360-degree rootball. Do you think the tree can take this without any die-back of limbs? I don't want to hurt the tree in any major way. The wall isn't worth it.

Besides damaging its brick planter, this yaupon holly threatens to engulf the gutters and roof, and so it ought to be pruned way back. (Special to the Democrat-Gazette)
Besides damaging its brick planter, this yaupon holly threatens to engulf the gutters and roof, and so it ought to be pruned way back. (Special to the Democrat-Gazette)

A I like your sentiments — valuing a plant over a wall — but I think your plant is too large for the site and needs to be pruned. Not only does the wall stand to suffer even more, but I worry for your gutter and roof as well. I would take action, but probably not as we head into summer. While hollies can be pruned a little in any season, severe pruning should happen in late winter to early spring. I would do some pruning now to start the process and do heavier pruning next year in late winter/early spring. Repair work on the wall can be done when the plant is dormant so the tree is less affected.

Retired after 38 years with the University of Arkansas Cooperative Extension Service, Janet Carson ranks among Arkansas' best known horticulture experts. Her blog is at arkansasonline.com/planitjanet. Write to her at P.O. Box 2221, Little Rock, AR 72203 or email [email protected]

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