May: To Do in the Garden

by Gary Crispell, EMGV

Rhododendron in bloom. Photo by A. Laine.

Ahh, May. The lovely month. The month for mothers, proms, college graduations and the first great beach weekend—Memorial Day. It is generally not too hot and rarely too cool. The month of balmy days that lead to enchanting evenings on the veranda (deck, patio, veranda—whatever). Enjoy the evening.  There’s gardening to be done on the morrow.

Lawn Care
Warm season grass people: It is your turn. If you didn’t fertilize the lawn in April, get to it. A good slow release fertilizer that meets the requirements notated in your SOIL TEST results is in order. Also, sharpen those mower blades.

Cool season grass folks: Just mow it, but not less than 3 inches high. “Do not,” he repeated, “fertilize cool season grasses until Fall.”

Fertilizing
Speaking of fertilizing; long season vegetable crops like tomatoes, beans and squash (among others) will benefit from a side dressing six to eight weeks after germination. (What?! You didn’t start your own from seed? You bought plants at a Big Box? Give them a week or two in the ground and then side dress.)

While you have the bag open throw some fertilizer at your summer annuals and perennials, too.

Azaleas and rhododendrons and camellias and other ericaceous (acid-loving) plants will benefit from a shot of acid fertilizer about now.

Planting
May is the second-best time in the veggie garden. (Everybody knows harvest is the best time.) It is time to plant beans (snap, pole, bush limas, etc.), cantaloupe, cucumbers, eggplant, okra, southern peas, peppers—sweet and hot, pumpkins, squash, watermelon and, for you non-competitive types, tomatoes.

Gladioli bulbs may be planted now as may begonias, geraniums and other annuals that you didn’t plant in late April.

Pruning
Spring flowering shrubs (e.g. azaleas, camellias, etc.) may be pruned as soon as the blooms fade.  Azaleas may be pruned until July 4th without cutting off next year’s buds.

Overgrown hedges can still be pruned.

Keep pinching back garden mums until mid-July.

Hand prune azalea and camellia leaf galls. They are generally not harmful to the plant, but are unattractive.

I realize your grandmother always cut back the daffodils and iris and other spring bulbs as soon as the flowers faded. I urge you to resist the temptation to carry on that tradition. The bulbs need that foliage to make the sugars that will provide the energy to bloom again next year. Wait until the foliage itself yellows before whacking it off and relegating it to the compost heap. The bulbs thank you.

Spraying

  • Always, always ONLY spray when necessary and READ & FOLLOW label directions.
  • Monitor rhododendron species including azaleas for borers. Spray if necessary.
  • Spray iris beds for iris borers which you probably will not see.
  • Scout for and spray as necessary for bag worms. They are on the move this month.
  • May is a good time to begin to try to eliminate poison ivy/oak (Rhus radicans) and Japanese honeysuckle (Lonicera japonica). Best wishes.
  • Begin spraying squash vines for borers.
  • Monitor the blueberry plants for borers. Spray as necessary.
  • Continue the never-ending spray programs for roses, fruit trees and bunch grapes.
  • Other insect pests active now include azalea lace bugs, boxwood leaf miners, euonymus and tea scales, spider mites (especially on coniferous evergreens), the ubiquitous aphids and the bane of my gardening existence—white flies.
  • If (or more likely when) your tomatoes show signs of blight, begin a fungicide regimen.

Other Things To Do in May That Could Quite Possibly Include the Garden

  • Dance around a May pole.
  • Celebrate Cinco de Mayo.
  • Mulch stuff.
  • Put out a flag on Memorial Day and thank a veteran.

Composting in Place

by Andrea Laine, EMGV

Late winter is one of my favorite times to work in the garden. This afternoon I enjoyed one of those days. The temperature was just right (55-degrees); The sun was shining after a solid week of rainy days; and I was engaged in a productive yet meditative task. I cut back a small stand of ornamental grasses: three pink muhly grass (Muhlenbergia capillaris), a beautiful native species, and one pampas grass (Cortaderia selloanna), a classic ornamental that grows fast and gets big.

Grasses generally require full sun and these two types are no exception. Well-drained soil is also a plus; a gentle sloping property like mine is perfect. These grasses are drought tolerant once established and deer resistant.

It is important to cut the dried ornamental grasses down to 4 to 6 inches from the ground annually in late winter. This affords new shoots the warmth of sunlight and better air circulation. The dried stalks are excellent brown additions to a compost pile, but I decided to practice “composting in place” instead.

grasses compost tools.jpg
I used a pair of freshly-sharpened manual scissor sheers to cut the dried stalks a few inches off the ground; and hand pruners to snip the stalks into small pieces which I let be where they fell atop the soil. This practice is called composting in place. Photo by A. Laine.

Highlights of Pink Muhly Grass

Pink Muhly Grass, four feet tall at maturity, is showy in the fall, at a time when flowers on many other plants have faded. It’s flower stalks feature wispy plumes of dark pink that gracefully sway with a breeze. Come winter the stalks fade to tan as do the grassy parts.

Highlights of Pampas Grass

Pampas grass can grow 6 to 10 feet tall and are hardy to Zone 7b. Mine was expanding almost too quickly when an unusually long cold spell in winter 2017 effectively set it back a few years in size. I have read that they are difficult to remove once established, so it may have been a blessing! It’s leaves are sturdy, flat and green. It’s flower is a light tan plume atop a tough tan stalk.

Sources and Additional Reading

Maintaining ornamental grasses:  https://extension.illinois.edu/grasses/care.cfm

Pampas Grass: https://plants.ces.ncsu.edu/plants/all/cortaderia-selloana/

Pink Muhly Grass:  https://plants.ces.ncsu.edu/plants/all/muhlenbergia-capillaris/

 

 

 

March: To Do in the Garden

by Gary Crispell, EMGV

IT IS MARCH!!! Stuff is blooming. Daffodils are regaling us with their perky yellow

Forsythia-viridissima---houroumono--CC-BY_d4qC3wy
Forsythia-viridissima—houroumono–CC-BY_d4qC3wy

blossoms as is the forsythia. I saw a quince in bloom yesterday. The periwinkle in the backyard is festooned with blue blooms. Well, at least the part that is above water. The saucer magnolia in the front yard is gorgeous although by the time you are reading this it may be a sad mess of frozen yuck. It would really be nice if it would cease raining long enough for us to get out and enjoy all this blooming.

Let’s be optimistic and say that it’s going to stop raining and get seasonably warm, so that getting out in the yard becomes a reality. Here’s your “To Do” list should all that actually occur.

Lawn Care
Cool season grasses (fescue and Kentucky bluegrass) can be fertilized with a non-slow release fertilizer such as 10-10-10. DO NOT fertilize cool season grasses after March 15 and do not use a slow release fertilizer now. Save it for Fall. Fertilizing later than mid-March will increase the likelihood of turf diseases in the heat and humidity of summer.

Apply crabgrass control to all lawns when the forsythia is in bloom and before the dogwoods reach full bloom.

Commence mowing activities when you can do so without losing your mower in the mud. Cool season grasses should be mowed at a height between three and four inches. Warm season grasses are still dormant; their turn will come later. Mowing frequency should be such that you do not remove more than one-third of the growth. Leave the clippings on the lawn to help reduce fertilizer needs by up to 25%.  If circumstances are such that more than one-third has to be cut, collect the clippings and use them as mulch. Grass clippings DO NOT belong in the landfill.

Fertilizing
Feed your shrubbery remembering “moderation in all things.”

Shade trees can be fertilized now, however unless you have poor soil (as indicated by your soil test) these plants can usually fend for themselves.

Emerging flowering bulbs can be fertilized now.

Fertilize asparagus beds early in March before the spears emerge.

Planting
This entire section is based on the rain stopping and the ground not refreezing and actually drying out (whatever that means; I’ve forgotten.)

Trees and shrubs can be transplanted now as well as fruit trees and grapevines up to bud break. Plants planted now will require more diligent water management through the summer than ones planted last fall.

Perennials can be planted now.

Start annuals and warm season vegetables inside if you haven’t already. (I know about you first tomato freaks.)

Rose bushes can be planted now.

Cruciferous vegetables (e.g., cabbage, broccoli, cauliflower) can be set out in the garden in the middle of the month.

Root veggies (e.g., potatoes, beets, turnips, carrots) can be planted in March as well as salad greens (e.g., lettuce, spinach, Swiss chard, kohlrabi and bok choy) can also be planted in mid-March.

Pruning
Prune fruit trees.

Deadhead spring flowering annuals like pansies (Viola x hybrids) as the blossoms fade to prolong flowering.

Roses can be pruned in the latter half of the month.

Overgrown broadleaf shrubs can still be severely whacked.

Spraying
Check for the following insect pests: euonymus scale, juniper-spruce spider mites, hybrid rhododendron borers. Spray as necessary following label directions.

Apply dormant oil to fruit trees to eliminate several insects. This is especially important if you have just pruned the trees.

Spray apple and pear trees in bloom with streptomycin to prevent fire blight.

Stuff to do to get ready for prime time
Check all your gardening equipment to ensure proper working order. You don’t want to spend the first really great gardening day running around looking for parts for your broken garden gizmo.

Think about experimenting with new varieties of annuals, perennials and veggies. Experimenting is fun and has few lasting side effects.

Plant a tree in honor of Arbor Day!  In North Carolina it is celebrated March 22.  https://www.ncforestservice.gov/Urban/nc_arbor_day.htm

 

Photo credit:  Forsythia-viridissima—houroumono–CC-BY_d4qC3wy, https://plants.ces.ncsu.edu/plants/all/forsythia-viridissima/


Groundcovers as Weed Control

by Andrea Laine, EMGV

After several years of trying to stay ahead of the weeds in my landscaped beds, I am coming around to an option I had not seriously considered before: planting ground covers as weed control.

Weeds

A variety of annual and perennial broadleaf weeds consider my yard home year round. Most of them I deal with by manually pulling. Dr. Joe Neal, professor of weed science at NCSU, recommends a frequency of every two to three weeks. Call me crazy, but I have never minded hand weeding. It feels meditative while I am doing it and afterwards, too, when I look upon my tidy garden.

Unfortunately, hand-pulling does not work for creeping woodsorrel (Oxalis corniculata L.). Even after a good rain and using a weed digger, it is difficult to get the root up on a younger plant. I find it easier to let it grow a bit which gives me more plant above ground to grasp and pull. But allowing any weed time to mature is dicey: weeds multiply so quickly and aside from being unsightly, rob your favored plants of moisture and nutrients in the soil. Encroachment is inevitable with woodsorrel as it spreads by rhizome, stolon and/or rapidly germinating seeds.

Ground covers

I used to view groundcovers as boring plantings; something you chose for a spot where it was difficult to grow anything else, or something non-gardeners or commercial properties planted to paint a spot green and call it landscaped. (Pachysandra comes immediately to mind.) But looking out my kitchen window last November at the way a few biennial columbine plants (Aquilegia canadensis) have reseeded so profusely over just a few years and now expertly cover a large part of the ground in one bed (i.e. no woodsorrell there), I am beginning to understand the concept and consider the possibilities.

ColumbineCover
Columbine isn’t traditionally considered a groundcover but it does the job nicely. All photos by A. Laine.

Groundcovers are plants that grow relatively close to the ground and spread freely to create a mass planting. The denser they are, the better they will be at shading the ground, thereby robbing weed seeds or rhizomes in the soil of the light needed to grow. If desired for weed control, seek out evergreen ground covers.

Columbine isn’t traditionally considered a groundcover but it does the job nicely. Some common groundcovers are already established in my landscape; pictured below left to right they are: golden creeping jenny (Lysimachia nummularia ‘Aurea’ ), creeping juniper (Juniperus horizontalis ), oregano (Origanum heracleoticum ‘Greek’ ) and Mrs. Robb’s bonnet (Euphorbia amyglaloides, ‘robbiae’).

 

A blank canvas

My thoughts of “too much columbine” have turned to “need more variety of ground covers.” Ground covers will be the new blank canvas. I am not choosing ground covers instead of more ornamental perennials and shrubs. I am choosing ground covers over open soil or a blanket of mulch which can be expensive and labor intensive when used for large spaces. Rather than fretting over too much columbine, I will consider it a placeholder and an organic mulch. When I am ready to plant something among it, I will simply edit out some columbine and insert a showier ornamental.

Where you have stubborn weeds, consider planting a more attractive groundcover. More plant suggestions appear in the links below.

Sources & Further Reading

About weeds

Identifying specific weeds:  https://projects.ncsu.edu/cals/plantbiology/ncsc/containerWeeds/list.htm

https://content.ces.ncsu.edu/are-you-weeding-frequently-enough-to-prevent-weeds-from-spreading

Creeping woodsorrel: https://plants.ces.ncsu.edu/plants/all/oxalis-corniculata-l/

About Groundcovers

This link lists dozens of groundcover suggestions for Georgia landscapes. Almost all will also survive in Durham County (Hardiness Zone 7).  https://secure.caes.uga.edu/extension/publications/files/pdf/C%20928_2.PDF

At heights of three to 12 inches, miniature roses can be groundcover:  https://content.ces.ncsu.edu/roses-for-north-carolina

Low-growing junipers make excellent groundcovers: https://content.ces.ncsu.edu/junipers-in-the-landscape

More groundcover plant ideas: https://www.missouribotanicalgarden.org/Portals/0/Gardening/Gardening%20Help/Factsheets/Ground%20Cover%20Plants66.pdf

 

NC Handbook for Gardeners

Book NCHandbookAmong the perks of being an Extension Master Gardener is receiving a comprehensive manual that accompanies you through the initial 40 hours of training and remains a trusted companion in the years thereafter. Now, for the first time, the North Carolina Extension Gardener Handbook, newly revised in April 2018, is available to all.

Written by a team of the state’s leading horticulture experts, the Handbook is a fundamental reference for anyone gardening in North Carolina or a neighboring southeastern state. It contains a wealth of information about the basics of gardening from soils and composting to vegetable gardening, garden design, and wildlife management. It covers maintenance of lawns, ornamentals, fruits, trees, and containers and specific management strategies for insects, diseases, weeds, and other pests.

The 728-page hardcover edition is enhanced with hundreds of color images, detailed graphics, diagnostic tables, case studies, and frequently asked questions. It normally retails for $60, but is currently on sale at  UNCPress.org for a 40 percent discount. (Use promotion code 01Holiday.)

A few more favorites

Here are a few more favorite gardening books chosen by this blog’s regular contributors.

The Southern Gardener’s Book of Lists: The Best Plants for All Your Needs, Wants, and Whims, by  Lois Trigg Chaplin. “This is an oldie but a goodie! Published in 1994 it has a plant list for everything in your garden. A few examples: Perennials for an Alkaline Garden; Trees with ‘Perfect’ Form, Shrubs that Bloom in the Shade, Perennials for Heavy Clay Soil … the lists go on and on!” – Kathryn Hamilton

Bringing Nature Home: How You Can Sustain Wildlife with Native Plants, by Douglas W.  Tallamy. “This book is both a motivational book and a quick reference for gardening with native plants in your area. The appendices are easy to use and the native plant lists for each area of the country are divided into different plant types for easy reference for your specific gardening needs: Shade and Specimen trees, Shrubs and Understory Trees, Conifers, Vines, Streamside plants, Ground covers and Herbaceous perennials, both dry & moist sites, Grasses, sedges and rushes and Ferns. I already gave my friend in British Columbia the list of natives for the Pacific Northwest. I go back to his native plant lists and butterfly host plant lists when I am trying to decide between two viable natives to plant and use his suggestion to increase the benefit to wildlife. The photographs of the insects are fascinating.” – Wendy Diaz

“The Triangle region is blessed with many places to explore nature – state, county and regional parks, or nature preserves like those managed by Triangle Land Conservancy. When I’m enjoying these places, I like to bring along Wildflowers of North Carolina by William S. Justice, C. Ritchie Bell and Anne H. Lindsey as a field guide. It contains 500 native or naturalized plants and though the entries are brief – two per page – there is a color image of each plant and enough pertinent information to help identify them in the wild.” – Andrea Laine  

Resources:

Purchase the Extension Gardener Handbook at:
https://www.uncpress.org/book/9781469641256/north-carolina-extension-gardener-handbook/

Learn more about the UNC Press Holiday Sale
https://www.uncpress.org/holiday-sale/

The North Carolina Extension Gardener Handbook is also available online in an open access format:
https://content.ces.ncsu.edu/extension-gardener-handbook