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LATE SPRING GARDEN CHORES

double file viburnum

Most spring bulbs are spent, and spring flowering shrubs are shedding their blooms.

Thus, It’s time to:

PRUNE

spirea

Prune spring-flowering shrubs, if needed.

Most shrubs and trees that flower in spring (like the Vanhouteii Spirea above, Lilac, Azaleas, and Deutzias, to name a few) begin to set their flower buds for next spring within 4 to 6 weeks of blooming.  Thus, if you wait to prune the plant after that 4 to 6 week window, you will be cutting off next year’s blooms.

White Camellia

Only prune your shrubs if they need it to control size or to shape the plant (e.g., limb up or espalier) or to remove dead or diseased branches.  Use hand pruners, and be sure to take a branch all the way back to a lateral branch (vs. shearing all of the top growth).  Camellias (above) need very little pruning, as they have a graceful growing habit.  Mock Orange (Philadelphus coronarius, below) is a straggly grower, and can use more help.  Mock Oranges are best planted toward the back of a mixed border where they recede after blooming.

Mock orange

DON’T prune summer flowering shrubs, such as Gardenia, Butterfly Bush (Buddleia davidii), Caryopteris and Beautyberry (Callicarpa).

deadheading daffs

Cut back dying foliage of spring-blooming bulbs, including Daffodils, Tulips and Hyacinth.  Capital Trees members Mary Anne Burke and Noni Baruch, above, deadhead the Daffodils planted along Dock Stree in Shockoe Bottom. Spanish Bluebells (beautifully photographed below by Helen Horseley) multiply over the years.

spanish bluebell

Photo by Helen Horsley

lady banks

Cut out all rogue branches on your Lady Banks Rose (above). You can tell a rogue branch -or sucker – because it is thicker, straighter, and produces no lateral branches.

climbing rose

Continue to train other climbing roses. Don’t be shy about removing many older canes to allow for a lighter, more elegant climber, like the one in Charleston, above.

rose

Continue to deadhead repeat-blooming shrub roses. Some of the heritage roses at Hollywood Cemetery, including the Doswell Rose, above, are still blooming.  I did a blog post recently about the incredible treasure these roses are at the historic cemetery.

iris

Remove spent flower stalks from perennials, such as Bearded Iris (Iris germanica), above, and Peonies (Paeonia), below. Some Bearded Iris will bloom again in late summer or early fall.

peony

Aster and zinnia

Photo by Melinda Hardy

Pinch back mid to late summer blooming perennials that tend to get leggy, such as Asters (above), Bog Sage, Daisies, Rudbeckia.  This will prompt the plants to grow lateral stems and create a bushier plant with more blooms.

Vinca minor

Keep Vinca minor (pictured above) and other aggressive ground covers pruned for a neat appearance.

DSC_0594

Cut back to the ground any unproductive Hydrangea branches. An unproductive branch is one that has no or little growth, or is brittle to the touch.

 

Maine ivy

Prune Climbing Hydrangea (Hydrangea petiolaris)  after it finishes blooming. Prune other climbers to keep shape.

Climbing Hydrangea is not just for walls — it’s fun to let it scamper across a bed or a low stone wall.

lenten rose

Cut to the ground browning leaves  and spent flower stalks of Lenten Rose.  Both Lenten Rose (Helleborus orientalis, above) and Stinking Hellebore (Helleborus foetidus, below) will generously self seed if not heavily mulched.

helleborus foetidus

Prune evergreens, if needed.

Evergreen shrubs, such as Hollies, Laurels and Ligustrum, tend to generate uneven growth that can be straggly looking.  It is fine to prune these shrubs now to shape them.  A couple of caveats:  don’t prune Magnolias or other evergreen shrubs blooming now, if you want to enjoy their blooms.  Only prune Sasanqua (fall-blooming) Camellias in early spring before they begin forming flower buds.

sweetbay mag

Prune multi-branch trees, such as Sweetbay Magnolias (Magnolia virginiana, above),  Japanese Maple (Acer palmatum) and Serviceberry (Amelanchier, spp.) to open up the plant and assist in developing a beautiful shape, by cutting out any volunteer sports and straggly branches. You can also cut suckers and stragglies of Chaste Tree (Vitex agnus-castus), but don’t cut back main branches, as they will be blooming in the next month.

wisteria

Prune Wisteria before it sets next year’s flower buds.

PLANT

Sam veggies

Plant summer vegetables and herbs

morning glory

Consider planting Morning Glory seeds for old-fashioned late summer blooms.  The vine twines through Japanese Anemone, above.

lotus

If you have a water garden, consider planting a Lotus (the native Nelumbo lutea).

I’d given mine up for dead and yanked the empty pot (empty except for mud) this spring.  As usual, my procrastination (laziness?) saved a life.  I went to toss the pot last week and, lo and behold, new Lotus leaves were emerging.  Can’t wait to see it bloom like it did last summer, above.

Fill your containers with summer annuals,which will reward you until a hard frost.  Be sure to regularly fertilize, as frequent watering depletes the nutrients from the soil. The window box below, on Meeting Street in Charleston, is filled with Begonia and Fern.

ferns and begonia

 

Add annuals to beds to replace plants that have gone dormant. New Orleans gardeners love to plant Caladiums in their otherwise evergreen borders for a shot of contrast.  You can also plant masses of Lantana or Plumbago for color all summer.  If you are planting in beds containing bulbs or dormant perennials, be sure not to disturb them.

DSC_0398

 EDGE

Edge your beelines and lawn borders.  The person who tends the garden below is on top of it!  Maintaining an edge between the lawn and pavement and between the lawn and planting beds helps keep the shape of the beds and prevents weeds from spreading.

Edge

WEED!!!!!!!!!!!!

BOXWOOD BLIGHT ALERT

 

BOXWOOD BLIGHT UPDATE Grasses

When I last reported about Boxwood Blight (Cylindrocladium buxicola) in my blog,  the only known infected plants in Virginia had been quarantined in a nursery on the North Carolina border. The nursery industry and the Virginia Department of Agriculture acted immediately to establish best practices to  limit the spread of the blight, and the industry, the government and academia have been working to find ways to combat the disease. Unfortunately,  these efforts have not succeeding in isolating the disease.  Boxwood Blight has now been reported   in residential gardens from North Carolina to Rhode Island, and has been confirmed here in Richmond. Studies have also found that Sarcococca (Sweetbox) and Pachysandra terminalis may also be hosts for the Blight.

 I’ve found Saunders Brothers Boxwood Nursery to be the most thorough and  current  resource for both historical and developing information on the Blight. If this is a subject that affects you, please check the Saunders Brothers website and your local extension agency for the latest updates.  The American Boxwood Society will hold its annual symposium May 14-16, 2014, and will devote significant time to Boxwood Blight.

THE SYMPTOMS:

  • Dark brown spots on leaves, may eventually cover entire leaf
  • Black streams on stems that appear to move from bottom of plant to top
  • Severe defoliation and dieback
  • North Carolina State University has some good images of plants infected with the Blight.

TREATMENT AND PREVENTION

  • It is now accepted, based on research in Europe where gardeners have been dealing with the Blight since the mid 1990’s,  that Boxwood Blight is not something that will be eradicated or even prevented, but is instead something that we need to learn to live with and manage (as we do with pysillid and leaf miner).
  • The United States Department of Agriculture recommends

     removing infected twigs, fallen leaves and the topsoil under affected plants because the fungus can persist on fallen leaves and debris.

  • Saunders Brothers recommends ensuring good air flow in and around plants, ample sunshine, and no overhead irrigation.  USDA recommends regular fall pruning to thin the branches of English Boxwood (Buxus sempervirens ‘Suffruticosa’) or other tightly growing Boxwood,  to provide air circulation, thus making it harder for the fungus to incubate and spread. This is especially important for tightly growing hedges.

  •  Saunders Brothers also reports that some “fungicides are very effective in controlling the disease, particularly when applied just before a prime infection period, which would be average temperatures in the 60’s to 70’s and complete wetting of the plant for an extended period”.  Please contact your trusted landscaper, extension agent or nursery for more specific guidance on this front.

LESS SUSCEPTIBLE CULTIVARS

 English Boxwood seems to be the most susceptible Boxwood to the Blight. Saunders Brothers and North Carolina State University are aggressively researching which cultivars of Buxus are most resistant to the Blight.  This from Saunders Brothers:

“We continue to work with the researchers at NC State as they do varietal susceptibility trials.  This spring we took a second load of plants to begin testing.  The good news is that early tests show several of the varieties we have grown for years appear to have very good resistance to Boxwood Blight.  ‘Green Beauty’, Insularis ‘Nana’, ‘Golden Dream’, ‘Winter Gem’, ‘Dee Runk’, ‘Fastigiata’, ‘Green Gem’, and ‘John Baldwin’ all show considerable resistance to the disease.  ‘Green Mountain’ and ‘Jim Stauffer’ both show some resistance.”

If you think your Boxwood are infected with Boxwood Blight, consult a trusted landscape expert and/or bring a sample (double-bagged) to your local extension office for diagnosis.