UACES Facebook Perennials

Perennials

August 2012

QuestionThe city of Little Rock has incorporated a plant into their landscapes and I need your help identifying it so that I can include it in my garden. It grows to about 3 feet tall. The stems are woody and dark brown. The leaves are long and narrow. The blooms are deep purple and the size of a half dollar. From what I can tell, the blooms open in the morning and are closed by mid-afternoon. I have enclosed a picture. It was taken in front of the Jim Dailey Fitness and Aquatics Center.

 

AnswerThe plant in question is commonly called a Mexican petunia-- Ruellia brittoniana. The standard variety is what is in the picture, and can be a bit aggressive, spreading to other areas of the garden. A dwarf variety, called Katie dwarf comes in purple or white and is much better behaved in the garden. Both are very drought tolerant and are perennials.      


August 2012

QuestionI have a perennial garden that is almost 20 years old. It is in need of an "extreme makeover", if you know what I mean. I have a lot of creeping Phlox that over the years has crept over the driveway. When I tackle this project in the fall, can I dig that up, clean it out some and replant it? I have noticed over the past 2 years that the blooms are not a prolific as before.

 

AnswerCreeping phlox actually tends to do better in poor soil, than rich, well watered areas. In my opinion, it is not the most attractive plant after it blooms. I do think you can clean it up, and replant this fall, but I would use it as a border or edging plant, and incorporate some other perennials and annuals into your bed. Diversity is a good thing, and you want plants that can bloom in all seasons. If your perennials get too crowded, it can reduce their vigor and their blooming. A general rule for perennials is plants that bloom in the spring, should be dug and divided in the fall. Fall bloomers should be dug and divided in the spring, and those that bloom in the summer can be dug and divided spring or fall.


July 2012

QuestionLike a lot of people, I'm losing some plants this summer. You may know that here in Maumelle, we're restricted to once-a-week watering. Even sneaking around my back yard with my hose isn't doing the job! You mentioned in your column today that hydrangeas are not drought-tolerant. I have one that's in a bad spot that I think I'll just take out after this year, so I know what you're talking about. My question is this: Would it be possible for you to print a list of plants that are drought-tolerant in an upcoming column? I've threatened to tear everything out and plant cacti next year or maybe just rosemary and Black-eyed Susans, since that's all that's doing well in my garden right now!

 

AnswerAs mentioned above with the crape myrtles, even they are struggling with the heat! Also, when planting even the most drought tolerant plants, the first growing season, they will need water. I can’t imagine what my landscape would look like with once a week watering—the soil is so incredibly rocky, and I am on a slope, so I feel for you with water restrictions. Deep, excellent soil encourages deep roots, which makes it easier to water less often. Some drought tolerant shrubs for sun include: abelia, althea (rose of Sharon), forsythia, spirea, buddleia (butterfly bush), barberry, junipers, beautyberry, nandina and ninebark. For shade, acuba, cleyera, and even camellias once they are well established. Perennials include rosemary, thyme, lamb’s ear, butterfly weed (milkweed), yarrow, gaura, rudbeckia (black eyed Susan), purple coneflower, liatris, sedum and penstemon. Annuals include lantana, periwinkle, cleome (spider flower), cockscomb, cosmos and portulaca. There are also a good number of succulents—plants with thick fleshy leaves that are available from nurseries.


March 2012

QuestionIn a recent column you talked about oleander, but you didn’t mention anything about the known toxicity of this plant. I’m talking about Nerium oleander, as I suppose you are. It is indeed an attractive plant. However, what I read tells me its greatest danger comes when the leaves are eaten, and it is more poisonous to humans and dogs (and some grazing animals including horses) than to some other species. I personally would forego it as a yard plant. But I recognize that someone else might decide differently, and so I feel strongly that anyone who chooses oleander ought to do so in full knowledge of its riskiness to children and pets.      

 

AnswerYou are correct that oleander is poisonous and I should have mentioned its toxicity. There are quite a few plants in our landscapes that fit this bill. The popular brugmansia and datura perennials are highly toxic, as is foxglove (Digitalis), hellebores (Lenten rose) and all members of the milkweed family. Even our common boxwoods and daffodils are toxic.


March 2012

QuestionI would like to transplant a big clump of decorative grass to a place in my yard that is near a water pipe. Should I be concerned about roots growing into the pipe? I ask because my neighbor has been told by a plumber that crape myrtle roots have caused her extensive plumbing problems. Now I'm paranoid about planting anything near pipes!

 

AnswerRoots can’t grow into a pipe unless the pipe has a hole in it or is cracked. Roots don’t break pipes, but if the pipe is damaged, they take advantage of the hole or crack and invade. I don’t think there should be reason to worry about planting ornamental grass.


January 2012

QuestionWinter Color 2012

 

AnswerPerennials are plants that come back for more than one year. While we surely hope our trees and shrubs come back every year, the term perennial is used for non-woody, or herbaceous plants in the garden. Here again, we have choices that bloom, spring, summer, fall and yes, even winter. Right now there are several species of hellebores that are blooming. Helleborus niger is the Christmas rose, and actually started blooming in my garden in early December. Helleborus orientalis or the Lenten Rose, typically doesn’t start blooming until February. New hybrids are now available at many nurseries with blooms starting in January, lasting through April. These plants are evergreen, but do their growing and blooming in the cool season. When hot weather arrives, they basically survive, but don’t do any new growing. In addition to a long bloom period, when color is definitely needed, they also do well in the shade. New cultivars also have upright flowers. A lot of plant breeding has been going on in the hellebore world, and there are many new choices. Colors range from reds, to pinks, whites and greens. Double flowers as well as singles are available. Italian Arum, Arum italicum is an interesting perennial for the shade garden. The variegated leaves are abundant now and quite showy. It will produce a spath-like blossom, and with the heat of summer, the foliage disappears, often leaving just a stalk with bright orange berries. The leaves are great in the winter garden. Don’t overlook rosemary as a shrub, groundcover or perennial. This culinary herb is evergreen and actually blooms in the winter months with a beautiful purple flower. Best planted in well drained, dry sites in full sun, it is easy to grow, and edible to boot.       


November 2011

QuestionWe have 6 pampas grass plants hiding our electrical box. Our neighbor on the other side put in maiden grass, which is doing great. Our pampas grass is 6 years old. After this past winter it did not come back well at all. The grass is not growing in the middle of these huge plants, but, on the sides. Also no plumes so far this year either. We did use fertilizer, but to no avail. We also cut them back in March I think. What should we do? Dig them up or hope for the best next year? Please let me know.

 

AnswerIt sounds like the crown of your plants has decayed. This often happens if the old foliage is not removed every year in February or March, or possible winter damage. If you only have a ring of foliage, you won’t get great plumes either. Pampas grass has a tenacious root system, so digging it up requires brute strength or a backhoe. If you can dig it up, cut out the dead areas and set it back out and basically start over. There are many other grass varieties to choose from, but all require annual pruning.


October 2010

QuestionI was given a Mexican petunia plant that is bare root and I plant to plant soon. What can you tell me about it? I have never heard of it before, am told it is very hardy and blooms well. It has 2 purple blooms on it now.

 

AnswerMexican petunia is Ruellia. It is an extremely heat and drought tolerant perennial. There is a standard variety that grows about three feet tall and has purple flowers and is very hardy. It can also get a little too happy in the garden and spread, so pay attention to it. There is also a dwarf ruellia that gets no taller than 6 inches and is marginally hardy in NW Arkansas. Plant yours in full sun and water and mulch it and it should survive the winter.


August 2010

QuestionAll this summer I have been trying to grow various heucheras. Every time I see an article or suggestion about shade gardens, these plants are encouraged. Because I have so many trees in my backyard, I bought at least seven or eight varieties and decided to re-pot them to keep them from drying out until I'm sure of where I'd like to plant them. But each time I bought some, the leaves dried up within days. The roots on each looked healthy, and the soil in each pot is kept reasonably moist (not wet). Do you have any idea as to what the problem could be?

 

Answer      There are hundreds of cultivars of heuchera on the market and some can take the heat and humidity of the south, and others look at it and die. When you are choosing heucheras look for Heuchera villosa in the parentage. H. villosa is much more heat and humidity tolerant than standard heucheras, and the plants should be evergreen for us--provided they have ample moisture--but in very well drained soil. Heavy soils and heucheras are not a good combination. Many recommend raised beds or even containers for heuchera care. Some varieties to try include: 'Citronelle', 'Caramel', 'Crème Brulee' and 'Frosted Violet'. Heucheras typically start to play out after three to four years, but there are so many plants to choose from you have lots of options.      


 

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