APRIL
2007

 

 

 

By
B. Rosie Lerner
 
Purdue
Extension
Consumer Horticulturist

 

 

 

 

 

04-05-07

Question and Answer

Q. I have some spearmint growing now. I can tell when I mow over it, but I don't know what it looks like. I would like to grow more but don't how to go about it.

A. All of the culinary mints have square stems and opposite leaves, with spearmint, in particular, having elongated-ovate leaves with coarsely toothed margins. Although many seed catalogs may offer seed packets, the best spearmint selections are of Mentha x piperita and can only be grown from cuttings or divisions, as the plants are sterile and, therefore, do not set seed. Take cuttings from actively growing stems or dig up a clump to divide. For more information on taking cuttings, see Purdue Extension bulletin online at http://www.hort.purdue.edu/ext/HO-37web.html .

Q. What is the best method for fluffing up the mulch already around my flowerbeds? Is it necessary every year to keep adding mulch?

A. Spring certainly did seem to bust out of the gates rather early and vigorously this year, though winter returned with a vengeance! Mulch is a great tool to conserve soil moisture, suppress weed growth and shade soil from excess heat in mid summer. Depending on what type of mulch you use, you likely will need to top off the flowerbeds each year or two. Generally, the finer the particle size of the organic mulch material, the faster it will breakdown. Ground bark mulch breaks down faster than shredded bark, which breaks down faster than bark chips. And the finer materials may pack down a bit, so fluff up your old mulch and top off with additional material, if the layer is less than 2 inches.

Q. We are moving to a new home that is an open field that has sat dormant for a long period of time. We will be having a house placed there soon. But I have many roses, bulbs, iris, lilies, lambs ear, hosta, lily of the valley, tall phlox, columbine, coreopsis, and clematis. When is the best time to move them? The ground is not yet broken for the house; we are to be out of here June 1st. Will it be safe to move all of these different plants and flowers and replant them then? I always thought it was best to do this in the fall, but I am afraid to leave all of my plants and flowers behind, and expect to recover them in the fall.

A. Well, there's no one perfect answer to your dilemma, since you have so many different species involved. Spring-flowering bulbs are best moved in the late summer or early fall while they are dormant. Most other perennials can be moved either in the fall or in late winter or early spring. Middle of the summer is about the worst time to move any of the plants, because that is the hottest time of year and when rains are less predictable.

It will likely be easiest to just start over with fresh spring-flowering bulbs this fall, rather than try to transplant those. For the rest of your plants, you may want to pot up small divisions of at least some of your perennials in good quality potting soil, and try to get them through the move that way until you have time to set your new garden. Or, if you have an out-of-the-way location at the new property, you could make a temporary nursery bed where you can move the plants and keep them pampered through summer, until you are ready to make your new garden. Keep the plants mulched and watered regularly.

Q. I planted three hydrangea bushes in 2005. Two pink and one blue. Last year, the blue one bloomed, but the two pink ones only had beautiful green foliage.

A. Ah, hydrangeas, you have to love them, even though this problem comes up year after year! It bears repeating, since the issue comes up for so many Indiana gardeners.

There are many different species of hydrangea, not to mention cultivars of those species. Bigleaf Hydrangea, H. macrophylla, is certainly the most popular hydrangea across the United States . This is the plant with huge flower clusters whose color can be pink or blue, depending on the soil pH (blue flowers in acidic soil, pink flowers in alkaline soil). Southern Indiana gardeners have some luck with this plant, but, unfortunately, for most Indiana gardeners, this particular species does not flower reliably. It normally blooms on previous year's growth, and, because it breaks dormancy very early, its flower buds are most often killed in normal spring frost. The vegetative buds often survive, or new shoots sprout from the roots if killed back to the ground, forming a tidy little foliage plant, but alas, no blooms.

There are some newer cultivars such as 'Endless Summer' and ‘Blushing Bride' that bloom repeatedly on current season's growth and so, while they may not have the huge blooms that southern gardeners achieve, they still provide wonderful color.

Q. I live in SE Indiana in Ripley County . From what I can gather from the Purdue Web site, "emerald ash borer" has not yet come this far south. I had planted about 5 years ago 160 ash trees. I assume the insect will eventually get here. If I have to treat the trees every year, it will certainly be an expense of both time and money. What are your thoughts? On the other hand, if I treat my trees, will the EAB eventually leave once they have done all the damage they can do in a given area?

A. I'm sure there are many folks wondering the same thing, whether they have just one tree or a plantation like yours! It is of course difficult to know when and where emerald ash borer (EAB) will go, but it is likely that over the years it will make its way down to your area, since it is already as close as Indianapolis and some nearby Ohio counties. On its own, it only moves about one-half mile or so per year. But, unfortunately, humans have greatly assisted this pest's travel plans by moving ash firewood, logs and nursery stock.

The Purdue Entomology Web site http://www.entm.purdue.edu/EAB/index.shtml has several resources to help you assess your situation, including a map indicating the counties where it has been positively identified, a chart to help you assess whether prevention is feasible and strategies for preventing EAB infestation. For a large planting such as yours, you might also want to consult with your Indiana Department of Natural Resources district forester; contact information is available at http://www.state.in.us/dnr/forestry/.

 

Writer: B. Rosie Lerner
Editor: Olivia Maddox,