June is National Rose Month

 

Glass lantern slide of an unidentified garden, c. 1920. Archives of American Gardens, J. Horace McFarland Collection.

We’re bringing our month of wedding-themed #ThrowbackThursdays to a close with tips for caring for roses at home from Smithsonian Gardens horticulturist Shelley Gaskins. Shelley manages the Kathrine Dulin Folger Rose Garden next to the Smithsonian Castle.

June is one of the most popular months for weddings, and it’s also National Rose Month! Roses are a traditional and elegant flower choice for wedding bouquets and decorations. Did you know that Tricia Nixon was married in the White House Rose Garden in June of 1971? The White House Historical Association has a new exhibit exploring the Rose Garden during the Kennedy administration opening on July 16^th. “The Kennedy Rose Garden: Traditionally American” features a few photographs and letters from the Archives of American Gardens. Did you choose roses for your wedding? Share your story in the comments!

‘Amber Queen.’ This rose, and all of the roses pictured below, can be found growing in the Kathrine Dulin Folger Rose Garden next to the Smithsonian Castle in Washington, D.C.

Rose Tip #1: Do your research! Roses are rated on several characteristics. Choosing roses that are rated as resistant to fungal diseases such as black spot and powdery mildew should top your list.

‘Angel Face’

Rose Tip #2: Roses require at least 6 hours of full sun (preferably in the morning), a well-drained and nutrient-rich soil, and moderate amounts of water. Water should only be applied directly to the root zone, not to the leaf surface. Adequate sunlight and water will help decrease the spread and incidence of fungal diseases.

‘Charlotte Armstrong’

Rose Tip #3: When pruning roses in early spring, prune with the understanding that opening up the center of the plant allows for light penetration and air circulation. Allowing light and air into the center of the plant will create an environment that is less favorable to fungal diseases. Be sure to clean the edge of your pruners with alcohol to avoid spreading viruses.

‘Grand Finale’

Rose Tip #4: Eliminating dead, dying and diseased plants and plant parts from your garden will help to keep your garden healthy. This includes cleaning up potentially diseased rose leaves that have fallen from the plant. Fungal spores can overwinter and return to the plant from the fallen leaves.

‘New Year’

Rose Tip #5: Not all bugs are bad! get to know the insects that visit your garden. Find out which insects truly pose a threat to the health of your plants (pests). Find out if the pest has any natural predators (beneficial insects). A healthy garden should have both. If necessary, you can introduce mail-order beneficial insects into your garden.

‘Purple Tiger’

Rose Tip #6: Beneficial insects are often beneficial only at certain stages in their life cycle. For example, the syrphid fly only feeds on prey while they’re in their larval stage. Adult syrphids don’t eat other insects, they eat nectar and pollen. You should plant flowers that provide a variety of nectar and pollen sources throughout the growing season.

‘Tropical Sunset.’

Rose Tip #7: Last one! Plant families that will help attract beneficial insects to your rose garden, including:

• Apiaceae (or Umbelliferae) -Carrot Family- attracts lady bugs, parasitic wasps, and predatory flies.
• Lamiaceae or Labiatae -Mint family
• Asteraceae -Daisy Family- attracts hoverflies, lacewing, lady bug beetles, minute pirate bugs, and spiders.

The Smithsonian Gardens Tree Collection: Proactive Management

This American elm tree on the grounds of the National Museum of Natural History is over two hundred years old. Eric Long, photographer.

The Smithsonian Gardens Tree Collection currently consists of over 1,850 trees, approximately 1,400 of which are located on the downtown Washington, D.C. and Anacostia campuses.  These trees add beauty to our grounds, and they offer myriad environmental and health-related benefits.  Unfortunately, it seems that trees are constantly under attack by a host of problems, ranging from severe climate, to native and exotic pests and diseases, to damage from construction and development projects, to the tough urban environment in which they grow.  Once these plants become stressed, it’s more likely that they will suffer due to one or more of these issues.  In addition, as trees grow, certain structural defects can develop which may cause problems in the future, especially when severe weather events can exploit the inherent weaknesses in these defects.

For these reasons, we at Smithsonian Gardens take a proactive, rather than reactive, approach to caring for these green assets.  Oftentimes, defects, cultural stressors, or insect and disease infestations that have gone unnoticed for a time can be difficult, if not impossible, to reverse.  Therefore, a thorough health and structure assessment of these trees was completed at the end of 2014.  This assessment consisted of a top-to-bottom, 360 degree visual evaluation of each tree.  All defects and other potential issues were noted and assigned a rating based on the severity of the condition observed.

Smithsonian Gardens staff band trees.

What we had at the end of the evaluations was a complete list of trees, their problems (if they had any), and recommendations for correcting anything of concern.  Based on the ranking system, we now have an organized and detailed list of what maintenance and tree care work is needed, with a clear indication of where we need to start.  This has enabled Smithsonian Gardens to find and fix issues before they become more serious, and gives us the ability to be proactive with our tree management.  It also gives us a better idea of how to budget for upcoming maintenance needs.  Prevention is the best medicine, and any time we can find and correct an issue before it becomes serious it allows us to keep our trees happy and healthy for many years to come.

-Greg Huse, Smithsonian Gardens Arborist and Tree Collection Manager

 

Winter Gardening Tips

The most important winter task is to take stock of your garden’s successes and failures. Mental notes are good, journal entries are better. There are plenty of mistakes to make, why repeat one?

Did you faithfully fertilize your garden during the growing season? If so, where are the leftovers? Don’t store them on your potting bench or your garden shed; bring them into an area that will remain above freezing. Some liquid fertilizers and pesticides become ineffective after freezing and thawing.

The winter months are the perfect time to take stock of the condition of your garden. Bonaire, West Orange, New Jersey, circa 1930. Ellen Biddle Shipman, landscape architect. Collection of the Archives of American Gardens.

Take advantage of warm winter days; clean up garden debris. Pests and diseases can overwinter on and in dropped fruit, vegetables, leaves and stems. Keep the garden clean and reduce the chance for re-infections. Being neat has the added benefit of reducing the amount of chores necessary in the spring.

When you are cleaning up the garden, don’t cut back the stems of subshrubs: lavender, Russian sage, perennial salvias, etc. The stems provide protection and a bit of insulation for the crown and the dormant buds. Wait till you see new signs of growth in the spring before pruning.

Talk a walk around the garden periodically to check on plants that may have “popped out” of the soil. Fluctuating soil temps – freezing and thawing – can push the perennials and pansies you planted in the fall right out of their holes. Dig the hole a bit deeper, replant and then smooth mulch around the plant’s base. This should keep the plant firmly grounded.

Use branches of pruned evergreens to protect tender perennials from wintry blasts. Maybe your rosemary plant will finally survive the winter!

Careless use of deicing products can damage both the home and the environment. To prevent damage to your home and the environment, choose a deicer carefully. Use deicers according to the directions listed on the package, if possible use even less than is recommended. Do not use fertilizer to melt ice and snow – the nitrogen and phosphorus in fertilizer can harm your local streams and the Bay. Plant damage caused by deicers can often be treated by soaking the affected area with 1-inch applications of water three to four times in the spring. As an alternative to deicers – use sand, ashes, or kitty litter to improve traction on icy areas.

Remember to water plants on warm days in January, February and March especially if there has been a dry autumn. Evergreen plants, particularly those planted in the fall, are most susceptible to desiccation.

Remove snow before it can accumulate by sweeping the branches upward with a broom to lift off the snow without further stressing the limbs.

Motivated to grow ‘green’? Use organic seed in next year’s garden. Check with the National Sustainable Information Service (https://attra.ncat.org/attra-pub/organic_seed/) for a list of suppliers of Certified Organic seed. Several seed catalogs located in Mid-Atlantic States appear on the list, including: Southern Exposure Seed Exchange (http://www.southernexposure.com/) in Mineral, Virginia, Landreth Seed Company (www.landrethseeds.com) in Baltimore, Maryland, and Seedway (www.seedway.com) in Elizabethtown, Pennsylvania.

-Cynthia Brown, Horticulture Collections Management & Education Manager