I’ll never forget the first time in Paris over 30 years ago. It was springtime, and the wisteria was in bloom. The smell and the purple flowers dangling in mid-air will be forever in my memory. Then, 4 years ago I moved to North Carolina, and in springtime once again saw wisteria. But, this time it was everywhere and somehow choking all the trees and shrubs it surrounded. I’ve learned there is invasive wisteria and native wisteria.
The invasive species are Chinese wisteria (Wisteria sinensis) and Japanese wisteria (Wisteria floribunda). The non-invasive, or native species of wisteria is American wisteria (Wisteria frutescens). If you want to incorporate a wisteria vine into your garden, a good option is the American wisteria. This deciduous wisteria blooms after the leaves emerge. Twines are counterclockwise woody vines that grow to 40 feet or more. Its stems are thinner than the invasive species, and they won’t damage wooden arbors or trellises. It’s well-suited for our planting zone.
The cultivar ‘Amethyst Falls’ has deep blue/purple flowers and blooms in spring and summer. The American wisteria is a larval host plant to both the silver-spotted skipper and long- tailed skipper butterflies, an added bonus of adding this plant to your garden.
(Left) American Wisteria (Wisteria frutescens) ‘Amethyst Falls’ is sometimes referred to as a dwarf variety because of the smaller leaves, flowers and more compact form, offers another native alternative for vine-loving gardeners. (Photo by David J. Stang courtesy of NCSU Plant Toolbox site). (Right) While beautiful, the Chinese Wisteria (Wisteria sinensis) can quickly become troublesome in the landscape due to its highly invasive nature. (Photo courtesy of NCSU Plant Toolbox site.)
Bull City Gardener Series-Live- Problem Solving and Propagation: Air Layering Tuesday May 17th, 10-11 am or Sunday May 22nd, 2-3 pm Briggs Ave. Community Garden
Learn to identify and treat common vegetable gardens problems, and even how you can prevent some before they get out of hand. Bring samples and stories from your own garden and learn how to handle whatever’s bugging you. For the second half, learn how to propagate plants by air layering, one of the most exotic and ancient forms of propagation. It uses the same principles as pinning a low branch to the ground, only with air layering, you bring the ground to the branch. It’s a good technique to use with trees and shrubs whose branches don’t bend down.
Durham Garden Forum: The Perkins Orchard Experience May 17th, 7-8:30 pm via Zoom “The Perkins Orchard Experience: since 1970” with Donovan Alexander “Alex” Watson, owner, Perkins Orchard. There are good reasons why Perkins Orchard is the largest and oldest produce market in Durham. For 51 years Perkins Orchard has been committed to high-quality service and products for the benefit of all in Durham. Please join us to learn about Perkins Orchard and their farming techniques.
We would like to continue increasing our membership and are asking your continued help to spread the word about the Durham Garden Forum to your neighbors and friends. Those who are interested in attending and/or joining can send an email to email@example.com and they will be sent a membership form. A Zoom registration link for this program will be sent out about one week before the scheduled presentation. If you plan to attend this program, you must register using the Zoom registration link. After registering, you will receive a join meeting link.
Just another confused spring. Our April showers all came in March and the winds of March have persisted throughout April not to mention the late frosts. Sheeesh! And May?? Who knows? Might be July hot or April cool or all of the above. Guess we’ll have to wait and see. There don’t seem to be any gopher prognosticators for the spring/summer interface.
At least the Accidental Cottage Garden appears to have escaped serious damage (mostly). The peonies (Paeonia officinalis) are spectacular as are the white with purple fringe iris (Iris x hybrid). I used to know their name, but I can’t remember anybody’s name anymore, so it’s the “Hey, you” iris. They are joined by two clumps of dianthus (Dianthus ‘Sweetie Pie’) and the little orange flowered plant. $100 (in Monopoly money) for an ID of it.
(Left to right) The Accidental Cottage Garden comes to life featuring Dianthus ‘Sweetie Pie’, iris, peonies (Paeonia officinalis), and a mystery plant with orange blooms despite unpredictable spring weather. (Photos by G. Crispell )
I suppose you really came to this for a gardening calendar, like it says at the top. If you insist.
Do you have a cool season lawn (Fescue or Bluegrass)? Recent research has indicated that fertilizing after mid-March will not cause a cataclysmic decline of your turf grass. The use of a balanced fertilizer (10-10-10 or equivalent) be used as opposed to a high nitrogen slow-release variety.
For those of us with warm season lawns (Bermuda, Zoysia) now is definitely the time to put out a high nitrogen (the first number on the bag) slow-release fertilizer. Y’all with centipede lawns would do well to wait until late May or early June to make a similar application.
Mow cool-season grass at 3”-4” and warm-season at 1 ½” to 2”.
FERTILIZING (other than grass)
Crops that take all season to produce or those that produce all season (subtle difference in wording—big difference in crop) would be most delighted with a feeding of a balanced fertilizer about now. Same goes for your annuals that will reward you with prodigious quantities of blooms.
Acid loving (ericaceous) plants (E.g. azaleas, other rhododendrons, camellias) can be fed with an appropriate amount of acidic fertilizer. (You know the appropriate amount because you got a FREE SOIL TEST earlier).
For ideal veggie planting times check out the NCSU website’s Central NC Planting Calendar for Annual Vegetables (see link in resources section below). The site is very helpful and includes flowers plus when, how, and how far apart to plant all things annual.
Grab those shears and loppers (the ones you sharpened and oiled in December) and put ‘em to work. Any of your spring flowering plants that need pruning should be pruned very shortly after they finish blooming. Many of them set next year’s buds within six to eight weeks of blooming. Pruning procrastination will have a deleterious effect on next year’s floral display.
Check azaleas and camellias for leaf gall. It doesn’t harm the plants, but it ain’t purty to look at. Just prune out the galls as necessary.
Keep garden mums (Chrysanthemums spp.) pinched until mid-July if your intent is a Fall bloom time.
I know your grandmother always cut off the foliage of her spring bulbs right after they finished blooming. Don’t. Just don’t. The leaves produce sugars (that’s what photosynthesis does) that feed the bulbs so that they can produce flowers next year. Wait until the leaves turn yellow before cutting them.
To prevent borers on iris, rhododendrons, blueberries (Vaccinium spp.) and squashes apply a properly labeled insecticide now.
Spray fungicide on all of your fruit trees & bunch grapes and any tomatoes that show signs of early blight.
Keep on keepin’ on with any rose programs.
Check trees and shrubs (especially evergreens) for bagworms. They are out and about this month as none of them has ever had the foresight to make a bag big enough to mate in.
Many vining undesirables are more susceptible to herbicide application right now while they are actively growing. Think poison ivy/oak (Toxicodendron radicans/T. toxicarium), honeysuckle (Lonicera japonica), English ivy (Hedera helix), etc.
OTHER THINGS TO DO FOR FUN AND PROFIT (well, fun anyway) IN MAY
Replace your pansies (Viola hybrids) with summer annuals. The pansies may still look decent, but as soon as it gets hot and stays that way they will whither and perish. Can’t take the heat and no way to get to the mountains.
Take those house plants outside and feed them. They will appreciate the outdoor vacation and the meal. Just don’t set them immediately in the direct sun. Let them get used to the light by setting them in a semi-shady spot for a few days. Coppertone doesn’t work real well on houseplants. They do not take to it kindly.
Pollen season should be over now. Wash the deck/patio furniture, raise the umbrella, pour a good cool beverage and sit down and enjoy the fruits of your labors.
*Resources and Further Reading
NC Extension’s Carolina Lawns: A Guide to Maintaining Quality Turf in the Landscape
When you hear the term gravel gardening what do you envision? A scorching hot parking median filled with river rock and a few struggling trees? A sparse desert landscape devoid of anything lush and showcasing only the prickliest of plants? Well think again. Gravel gardening (also known as scree or dry gardening) offers so much more. You will now find gravel-type gardens starting to pop up at some of the world’s most beloved botanical gardens—including Chanticleer and our own NCSU’s J.C. Raulston Arboretum and Duke’s Sarah P. Duke Gardens. Juniper Level Botanic Garden in Raleigh has also adopted and amended this method with its very own crevice garden, substituting gravel with 100 percent PermaTill®, a pea gravel-like product made of slate found in North Carolina. Gardening with gravel and other hardscape materials offers a sustainable, lower-maintenance option that doesn’t sacrifice beauty. Legendary English gardener Beth Chatto, a pioneer of this style of gardening, described this type of method succinctly when she said, “This garden was not to be irrigated in times of drought. Once established, the plants must fend for themselves or die.”
So if gravel gardening is good for the environment and good the gardener, what is it exactly? Typically, gravel gardening involves putting in some upfront work. It means creating a garden bed 4-5 inches deep with gravel laid directly on top of soil. The gravel should be uniform in size and can vary from pea gravel to ¼ inch and must be igneous or metamorphic rock, so it won’t break down over time. Typically, gardeners use their existing soil without amendments (J.C. Raulston has turned PermaTill® into their scree garden), and good drainage is a must. Equally important in the design is an even thickness of gravel throughout—especially out toward the edges. More shallow areas of gravel only invite weeds. To achieve this, a good gravel garden should have a border 4-5 inches in height. Bricks, metal edging, or even rocks are all options; you could even make the gravel garden a raised bed. Gravel acts like mulch here: it suppresses weeds and means very low maintenance in the future. When preparing a site with gravel for this method of gardening all existing plant material should be cleared prior to planting.
Gravel gardens are intended to be in sunny, hot, and dry locations. Drought tolerant plants are the right choice for these hardy gardens. While gardeners should plan to do a good deal of watering the first year while the plants’ roots are getting well established, this diligence will pay off. This method’s water-wise and low-maintenance features really come into play in subsequent years as plants should require no supplemental irrigation thereafter. If properly prepped at installation and their spent plant material cut back well each spring, these gardens are devoid of many weeds and easy to maintain once they grow in.
In terms of garden design, many gardens grasses like our native Muhlenbergia capillaris (pink Mully Grass), Schizachyrium scoparium (Little Bluestem), and Nasella tenuissima (Mexican Feather Grass) make excellent backdrops for gravel gardens and offer great fall color and wintertime architectural interest. And while cool Cacti, Yucca, Agave and types of Euphorbia work quite well, options abound, including many natives. Some good choices for gravel gardens in our area also include the following:
Achillea milefolium (Yarrow)
Allium (Ornamental Onion)
Asclepias tuberosa (Butterfly Weed)
Clinopodium carolinianum (Georgia Calamint)
Echinacea purpurea (Purple Coneflower)
Lavendula angustifolia (Common Lavender)
Nepeta sp (Catmint)
Penstemon (Beard Tongue)
Salvia rosmarinus (Rosemary)
Salvia yangii (Russian Sage)
Stachys byzantina (Labs Ear)
Verbena canadensis (Rose Verbena)
At once earth friendly and gardener friendly, this low maintenance method could be a great addition to your garden repertoire.
Further Reading and Additional Photos of Mature Gravel Gardens
I recently heard the term wolf tree, and wondered what in the world that could mean. I have since learned the meaning of the term and the significance of these trees, and have discovered that we have one on our property in northern Durham county.
When settlers from Europe came to this country, they felt the forest was in their way. They were used to open fields, grazing animals and plowed soils. As they took over and cleared land, a few trees would be saved to shade the farm animals and produce nuts for the squirrels. Without the usual competition from neighboring trees common in a forest setting, the lone trees would send branches out laterally to to expose their leaves to the sun, rather than having to grow quickly towards the sky. The lower limbs of a wolf tree would not become senescent due to the shade of neighboring trees and the profile of the tree would be very different from the same species growing in the forest.
When I first saw the wolf white oak on our property, I thought something was wrong with it and that it might be dying. The main trunk was short, maybe 15 feet, and there were too many branches, some nearly horizontal. I have learned that this is common for a solo tree in a pasture setting. If the pasture is abandoned, new trees will grow but the wolf tree might have a 100 year head start, so it retains its branching habit. Our tree is easily seen in Google Earth images, surrounded now by evergreens, mostly pine and some cedar. The pasture is no longer recognizable.
Wolf trees can be quite old. I measured the circumference of ours to be 14’ 9” at chest height, and using the tree age calculator, this tree started life in about 1740! That is amazing. Decades before the American Revolution. Beneath this tree, not seen well on the photograph, is a low stone wall surrounding an abandoned Cemetary. There are seven grave stones, and some are legible, dating to the 1850s. The tree would have been ~100 years old at the time, and the loan tree on the edge of the pasture was a perfect place for the grave site.
The term wolf tree may have originated from the appearance of the tree surrounded by much younger trees, like a lone wolf surrounded by other animals who are protecting themselves from being singled out for the kill.
These trees were once thought to be problematic from a forestry standpoint. Their multiple low branches meant that there were not long stretches of available wood for harvest, where as the same tree in a forest setting might have 60+ feet of trunk. The trees were thought to use up a disproportionate amount of nutrients, and removal was recommended in older forestry texts. It is now known that these trees actually provide significant habitat for birds, reptiles, insects, and mammals, ecological services that far exceed those provided by forest trees in a per tree comparison. These giants are to be treasured. I wonder how many this old still remain in Durham County.