IN THE GARDEN: Dianthus take a break in summer while new shrubs need water


Q : I bought a plant at Walmart that had this tag "Accent Strobilai" on it but no other care information. Can you help me identify the plant and tell me how to care for it -- sunlight, shade? It has large purple leaves. Thanks.

A:  Without seeing the plant, I am going to guess they are talking about Strobilanthes atropurpurea, commonly called Persian Shield. It has beautiful purple and green leaves with a silvery sheen; they are quite dramatic. I am including a picture of one I grew last year. They do best with filtered sun in the morning and afternoon shade. They would not do well in full sun, particularly in the afternoon. I have grown it in containers, but planted in the ground, it might come back from the root system in a milder winter in the southern half of the state. It thrives in heat and humidity, so it should be happy now!

Q:  This blackjack oak is within 20 feet of the house (see reader's photo). While cleaning up from the tornado, we noticed these hard masses at the foot of the tree. They look like mushrooms but are much more dense. Should they be removed? Do they signify the demise of the tree? Your guidance will be appreciated.

A : I think it is a type of shelf fungus, which grows on decayed or rotting wood. I would guess you have a large, woody root beneath it that is decaying. How does the tree look? Is it fully leafed out and growing well? If decay gets into the heart of the tree, you can see more mushroomlike growths appearing on the trunk. Unfortunately, once decay begins, there is very little you can do to stop it. If the tree is otherwise healthy, continue to water it when it is dry. Do pay attention. Trees don't typically die overnight. If a tree is beginning to decline, you will see some limb dieback, and often the leaves will be smaller or less full. Hopefully, it will not affect your tree. You can remove the fungus, but if there is decay, you could see more.

Q:  I bought several of these little bundles of purple blooming joy a few months ago and planted them just right according to the directions, in an east-facing bed where they get a good six hours of full sun each day (see reader's photo). Look at them now! ... Not only have they stopped blooming, but it appears that every bud has developed a brown sheath. Have I overwatered? I doubt it. Do they prefer shadier conditions? Finally, what are they called, as I have forgotten? And might you recommend something different that stays low and compact and blooms nicely? Thanks for your sage advice.

A:  Just be patient. The plant in question is a dianthus, a cool-season annual/perennial. Cool is not the season we are in. Dianthus typically slow down or stop blooming in the heat of summer. If you can keep them alive with some water, they should bounce back and bloom again in the fall. Many of them will overwinter and bloom both spring and fall in the garden, but usually not a whole lot in the summer.

Q:These leaves are from the center part of the tree in the photo (see reader's photo). It was just planted this spring and has beautiful blooms. Is this a fungus or soil deficiency or watering problem? I have read a lot about magnesium deficiency in hydrangeas, but I don't want to put that on it when I don't know what is wrong.

A : The overall plant looks good. Since it was just planted this spring, and it is such a large plant, I am going to say the plant is suffering from transplant shock -- adjusting to its first growing season with a more limited root system, especially now that the temperatures have increased and we have had little measurable rainfall. Make sure you do a good job of keeping it watered to ensure the roots get established and spread out. While I do see a few leaf spots, that can come about from stress too. Just enjoy it this summer and keep watering, and see what happens. If the situation deteriorates, let me know.


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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 jcarson@arkansasonline.com


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