Annuals Archives

Alternatives to Impatiens

by Marian Parsley, Behnkes Manager of Annuals

Impatiens are getting a lot of attention these days and it’s not the kind of attention gardeners want to hear. You may not be aware of the problem, but our most beloved shade annual is at risk from a new fungal disease.

The symptoms of the disease, which is called Downy Mildew, begin as slightly off-color foliage (slight yellowing) and slight wilting/curling down of foliage. If weather conditions are favorable, the disease continues to progress, causing all of the leaves and flowers to drop off, and ultimately, the plant dies.  The disease affects the standard, seed-grown impatiens; there are some other types of impatiens that are resistant to the disease (see below).

Although commercial growers can control the disease in their greenhouses through application of chemicals, this is not practical in the garden center or for the homeowner.  We have decided not to carry the traditional impatiens plants at our garden centers until the plant breeders develop disease-resistant strains. Rest assured that this is a high priority in our industry.

All is not lost; there are many alternatives to old-fashioned, seed-grown impatiens. Listed below are some suggestions for some wonderful plants for you to try in your shade garden.

Disease Resistant Impatiens:

New Guinea Impatiens

New Guinea Impatiens

Sunpatiens and New Guinea Impatiens–Neither is susceptible to Impatiens Downy Mildew so they’re an excellent alternative.  Sunpatiens are more vigorous than the traditional New Guinea series and will bloom in both sun and shade. The key to growing any New Guinea Impatiens is providing ample water.

Divine Series New Guinea Impatiens–Delivers outstanding color options and garden performance, heat and drought tolerant. Provides masses of flowers all season long.

Begonias:

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Wax Begonia (L) and Tuberous Begonia (R)

– Classic, Old-fashioned Wax Begonias–Wonderful in mass plantings, color until frost and perform well in sun or shade. Low maintenance.

– ‘Big’ Begonia–They look like a wax begonia but are the size of the dragon wing-type begonia. The flowers of the Big Begonia stand atop the foliage in addition to the sides of the plant making it ideal for the landscape.

Dragon Wing Begonia—simply one of the most beautiful begonias ever! Large red blooms on wing-like light green foliage. Spectacular in the sun or shade garden.

– ‘Sparks Will Fly’ Begonia–A real stunner in the garden or patio shade containers; gentle orange blossoms, beautiful dark green almost bronze foliage, mounding growth habit.

– ‘Whopper’ Begonia… Extra large blooms, huge plants with shiny bronze foliage. Minimal maintenance requirements. Makes a bold statement in the shade garden.

Tuberous Begonia: An old favorite, large camellia-like blossoms, green or bronze foliage. Wonderful in the shade garden.

Caladiums

Caladiums

Caladiums: Showy, tropical looking foliage with unique patterns, excellent choice for containers or the shade garden.

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Coleus

Coleus: A classic shade-lover in a variety of colors and shapes.

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Torenia

Torenia: Also known as the wishbone flower because if you look closely in the center of the flower there appears to be a wishbone. Great color choices, including beautiful blues—a color not found in impatiens.

Wintering Over my Favorite Coleus

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This was my coleus collection just a few weeks ago.  Three plants had become a massive, eye-catching display on my patio, a display I didn’t want to say goodbye to just because of, you know, freezing temperatures that would kill the coleus in an instant.

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So I brought at least this relatively small potted-up coleus indoors, where it sits in a position of glory on my kitchen island and still looks good in late December.  (So far, so good.)

Rooting from Cuttings

Gardening wisdom dictates that what I should have done, and still might do, is to take cuttings from this, my favorite coleus, to plant outdoors again next season.  And indeed, it’s apparently easy as pie to do it. (Here’s how.)  But it’s also apparent that I should have started that process in the fall, but hey, better late than ever.  Besides starting weeks ago, there are several tricks to succeeding at coleus cuttings:

  •  To avoid root rot, let it dry out, watering only when the soil surface is really dry.
  • Give it enough light – the sunniest windowsill or artificial lite.
  • In spring, gradually acclimate the plant outdoors in bright light and then to sun outdoors.

As Whole Potted Plant

Alternatively, I could try to keep this whole plant going until I can put it outdoors again next May.  Here’s what it’ll take to survive indoors as a whole plant:

  • Enough moisture.  It’s important to water as soon as the top of the soil is no longer moist, so I’ll check a couple of times a week and water immediately when the topsoil is dry.  It’s good not to let it sit in standing water, though.
  • Enough heat.  Coleus likes room temperatures of 50 and above.
  • Enough humidity.  The more the better.  It’s a tropical plant.
  • Enough light.  My brightest window, or artificial light.

If the plant starts to lose its leaves, it’s probably too dark or cold.  If it goes into flower, I’ll snip off the flowers to encourage vitality, and pinch off growing tips to encourage bushiness.

In the spring, I’ll cut it back, refresh the potting soil a bit, and voila – it’ll become huge again quite quickly.

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Next season I’ll be planting coleus not just in pots but IN the garden, too.  Look how great they look growing that way!

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Posted by Susan Harris.

Poinsettia News and Care Tips

Happy National Poinsettia Day, everyone!  And to honor the occasion, how about some poinsettia news and tips on their care?

In news, poinsettias last longer today than ever before, thanks to the introduction of new hybrid varieties.  New varieties in white, pink and marbled colors abound.  Plus, spray-painted options come in every imaginable color.

If they’re properly cared for, the poinsettias available today will last up to 6 to 8 weeks.  These tips for accomplishing that are in line with the best practices recommended by the University of Maryland.

Poinsettias in a traditional display at Longwood gardens.

Care of Poinsettias

  • Keep poinsettias someplace with temperatures between 65 and 75 degrees.
  • Keep them away from drafts from heat vents, doors or windows.  Drafts will cause leaf and flower drop.
  • Place the poinsettias where they receive bright natural light, but no direct sunlight.  Direct sunlight will cause leaves to yellow and flowers (actually, bracts) to drop.
  • Best artificial light for poinsettias are cool white fluorescent bulbs.
  • Check the soil moisture daily and water plants only when the potting medium is DRY.

For a Second Season

After the holidays are over, it IS possible to make poinsettias last for a second year, though the size and quality of the second year’s display probably won’t be as good.   Click here for instructions in what that source refers to a “fussy, exacting process.”  So, you’re warned!

Posted by Susan Harris.

Why I Clean my Beds NOW

Something that gardeners sometimes disagree about is whether to clean up their beds in the fall or wait until spring, and I was interested to learn that horticulturist Carol Allen is in the clean-up-in-fall school.  In fact, her garden is free of dead leaves and all mulched over by the end of December so that in early spring her garden is ready for prime time!

Well I’m with Carol on this one, and here’s one reason why:  I’d rather not look at dead, brown leaves all winter!  Especially close-up to the house, I’d rather see a scene like the one below, post-leaf-removal.

Cleaning up also inspired me to add some ornamental kale to this high-visibility spot.  I love how this purple variety looks with the chartreuse Creeping Jenny groundcover.  I used five of the same kale here because in such a small space, any more would look busy to my eyes.  I keep reminding myself that in my new small garden I need to keep it simple.

Besides aesthetics, another reason to remove leaves is to keep wet leaves from killing certain plants – the ones that like to stay dry.  That includes, in the photo below, Lamb’s Ears and all my groundcover Sedums.  So while I’m waiting for all the leaves to drop to do the big clean-up in this spot, I at least unsmothered these dryness-loving perennials.

In the lower part of this photo are plenty of leaves, but they’re on top of perennials that can handle it, like black-eyed Susans.

Want more reasons for doing fall clean-up?  It removes diseased plant parts that may winter over, and spots for garden pests like mice and voles to winter over, too.

Posted by Susan Harris.

Fall Color for Shady Spots

I’ve reported on on my favorite plants for fall color in sunny spots and as promised, here are my faves for shade.

Annuals

Coleus come in dozens of colors and patterns.  Mine are just now, in late October, losing their leaves.  They’ve looked big and bold and colorful all season, until let’s say m id-fall.

Perennials

Begonia grandis.

Begonia Grandis blooms from September through fall.  The foliage is gorgeous all season.

Japanese Anemone in mid-October.

Japanese Anemones look great here at the National Gallery’s Sculpture Garden with petunias.

Hakonechloa Grass.

Hakonechloa Grass doesn’t bloom, but its gold foliage looks great all season and the dried foliage looks lovely in the winter, too.  Behind it is a shrub that’s colorful in the fall and winter, too – the  Acuba.

‘Ice Dance’ Carex.

Carex is the name of a large genus of grass-like plants (technically called sedges, not grasses) and many are evergreen, like the ‘Ice Dance’ variety above.  It’s been a primary groundcover in my shade garden for decades now.  It brightens up even the darkest spot.

Shrubs

Oakleaf Hydrangea at Brookside Gardens.

The glorious Oakleaf Hydrangea  is one of my all-time favorite shrubs and it’s famous for its four-season interest.  The photo above demonstrates its fall glory and coming up next, with no leaves in sight, is its lovely exfoliating bark.

Encore Azaleas

Encore Azalea is a repeat-blooming shrub was highly recommended to me just yesterday by a Prince George’s Master Gardener.  She told me that hers are blooming like crazy even now, in late October.

Posted by Susan Harris.  Photo credits:  Encore Azaleas.  All others by Susan Harris.

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