Coleus: The Queen of Foliage Plants

Coleus varieties:
Top row (l-r): 'Saturn', 'Lord Voldemort', 'Pistachio Nightmare', Middle row(l-r): 'Religious Radish', 'Sedona', 'Beckwith Gem', Bottom row: (unknown yellow variety), 'Alabama Sunset' and 'Fishnet Stockings.'


Coleus (Solenostemon scutellarioides) are summer annuals here in the Pacific Northwest although they are perennial in their native range in SE Asia and when planted in the mildest regions around the globe. It is safe to plant them in the PNW near the end of May each year when evening temperatures are in the mid-40's F. They more than compensate for their late start by providing glorious foliage all summer and a wealth of possibilities for combinations when paired with other plants. They are available in a wide range of colors and make perfect accents for mixing with other annuals in bedding schemes or in container plantings.

Previously grown in generations past as a Victorian conservatory (greenhouse) plant, earlier forms have been vastly improved upon in recent years by the efforts of superior breeders. Today's varieties are generally tolerant of both full sun or shade, making them extremely versatile without much worry about their light requirements (with the exception of some of the pale yellows, ie. 'The Line' which should be kept out of afternoon sun). They are generally very easy to grow if you purchase healthy plants at your local garden center. They require good drainage and regular feeding, as per other summer annuals. It is helpful to pinch off any flowers that may form on the terminal shoots to produce a fuller, more robust plant. Most varieties will grow to between 12 and 15" tall and wide although both larger and smaller varieties are available. Try Wells Medina Nursery in the Seattle area for an outstanding selection of these beauties.

Cheers, Tim

May To-Do List

Syringa vulgaris (Common Lilac)

To Do In May:

Finish mulching garden beds and applying organic fertilizers.

Continue treating for slugs with iron phosphate products like Sluggo.

Start staking and training climbing plants like clematis to prevent flowering stems from breaking.

Stake perennials such as peonies and delphiniums to prevent breakage of stems, especially if rainy or windy.

Continue to pull weeds before they go to seed. Pull or treat dandelions in lawns.

Shop for the remainder of your summer annuals and vegetables, although it is advised that you wait (if supplies hold out) on tomatoes, basil, coleus, New Guinea impatiens, zinnias and a few others until evening temperatures are above 50 degrees F. If you purchase tender annuals, you can keep them outside during the day and bring them into the garage at night until it is safe to plant them.

Deadhead rhododendrons as soon as they finish flowering.

Be careful to water if we suddenly have nice weather. As it gets warmer, the garden can dry out very quickly, especially new transplants.

Happy gardening. Cheers, Tim

April To-Do List

Yoshino Flowering Cherries in bloom on the University of Washington campus - 4/5/09


To Do In April:

Mulch garden beds with compost or manure .

Feed plants with organic, all-purpose fertilizers. Apply alfalfa meal to heavy-bloomers such as roses and dahlias.

Treat for slugs with iron phosphate products such as Sluggo.

Pull or treat weeds before they flower and go to seed. This will save you hours of work in the weeks and months ahead if you do a thorough job now.

Make sure that hoses, sprinklers, etc. are in good working order in case of an early dry spell in our weather.

Pay special attention to water containers and new plantings in the event of an early dry spell.

Begin to prune boxwood and other broadleaf evergreen hedging plants as needed. For spring bloomers such as Choisya ternata or Viburnum tinus, prune immediately after flowering.

Prune roses if you haven't done so already. New buds and shoots will be reddish in color.

Inspect perennials and roses for aphids and treat as necessary with insecticidal soap (not detergent soap) or other nontoxic solution. Be advised that pyrethrin-based insecticides are known to burn new growth on some plants and many stronger insecticides can kill off the aphids' natural predators (ie. ladybugs).

Shop at local nurseries for peak selection of trees and shrubs, especially hard-to-find items.

Only plant the hardiest of spring annuals and vegetebles until mid-May when evening temperatures are consistently above 45 degrees F.

Hardy spring annuals would include bacopa, lobelia, marigolds, pansies, petunias, snapdragons, dusty miller, etc.. Wait another month for zonal geraniums, coleus, impatiens, begonias, etc..

Hardy spring vegetables would include carrots, celery, lettuce, green onions, mustard greens, Swiss chard, broccoli transplants, parsley and most herbs. Wait to plant tomatoes and basil.

Tomatoes and basil should not be planted out in the garden until the evening lows are above 50 degrees F. Due to high demand you may need to buy them prematurely. If you do, you'll need to keep them outside during the day and then move them into the garage or a greenhouse at night to protect them. You may plant them when it is safe to do so in the days ahead.

Take time to get out and enjoy the beauty of spring. Take a stroll trough the Quad at the UW (see photo above), a trip to a public garden or just a walk around the neighborhood. We could all use some fresh air, Vitamin D and a few flowers to lift our spirits after all the nasty winter weather and gloomy economic news. Spring is here and summer is coming.

Cheers, Tim

Garden Peonies

Top row (l-r): 'Gay Paree', 'Festiva Maxima', 'Bowl of Beauty', Middle row (l-r): 'Red Charm', 'Comanche', 'Krinkled White', Bottom row (l-r): 'Kansas', 'Sarah Bernhardt', 'Illini Warrior'

Peonies are among the most beloved of all garden flowers available with its uses tracing back roughly two thousand years to China. Over four thousand varieties exist in cultivation today in a vast array of colors and forms. Many varieties are fragrant and virtually all possess attractive foliage that looks good all summer. They are exceptionally long-lived plants and their blooms make exceptional cut flowers.

The biggest challenge to growing peonies in the Pacific Northwest is keeping the plants free of Botrytis paeoniae, a devastating fungal disease that can occur when plants are not grow in optimal cultural conditions. This disease can be recognized as soft brown or brownish-red areas developing at the base of leaves and shoots which then wilt or collapse. Peonies require fertile, well-drained soil and would prefer four hours or more of direct afternoon sun. Aside from buying infected plants, you should be free of problems once you've made sure that you've sited your peonies properly.

When planting, it is also helpful to know that peonies resent being planted too deeply. Herbaceous peonies (those that die back completely each fall, stems and all) should be planted with their 'eyes' or growth buds right at the soil level. Tree peonies should be treated as shrubs, with the base of their stems kept at or above the soil level so that they don't develop root rot. Peonies also resent being overfertilized or disturbed after they've been planted. A little compost each spring is about all that they require.

When shopping, it is very important to avoid selecting varieties based solely on photographs from books or catalogs. This can be extremely disappointing. It is very helpful to observe varieties in bloom or to buy 'tried and true' varieties from reputable nurseries that are familiar with what grows well here in our region. It should be noted that peonies do vary in their bloom times by several weeks and many of the double-flowering varieties have a tendency to flop under all of our rain. Since many peonies require some staking, you may also wish to seek out some of the smaller dwarf and 'rock garden' types which are wonderfully maintenance-free. My final caveat is that young plants often do not bloom the first year and take about three years to become fully established. Your patience will be rewarded many times over.

Cheers, Tim

NPA 'March Mania' Plant Sale at BBG

Helleborus x hybridus - Rose Madder Strain


Important Reminder For Gardeners On A Budget:

NW Perennial Alliance's 'March Madness' Plant Sale
This Sunday March 8th at the Bellevue Botanical Garden (11 a.m. - 3 p.m.)

The NPA's annual spring sale (formerly known as the 'Hellebore Open House') has been an annual mecca for collectors of rare woodland plants and ephemerals. This year, however, they will also be selling off a massive number of plants that have been removed from the Bellevue Botanical Garden's NPA border during its current renovation for once-in-a-lifetime prices. Good garden plants, hellebores in particular, may not be available at these prices again anytime soon. Don't miss out on these good deals. Happy hunting. Cheers, Tim

MARCH TO-DO LIST

Narcissus 'February Gold' blooming earlier today (3/2)



MARCH TO-DO LIST:


MULCH GARDEN BEDS: Spread compost in all of your garden beds but be mindful not to bury the stems of your trees and shrubs. Many drought-tolerant perennials and herbs are also resentful of being buried. This mulch will feed your plants all season and keep their roots cool in the summer months ahead.



WATCH FOR SLUGS: Apply SLUGGO or other brand of Iron phosphate pellets around your emerging perennials to prevent slug damage. It is safe to pets and wildlife.



PRUNING: The beginning of March is an ideal time to prune roses. Remove thin, scraggly growth and preserve the stronger canes for the framework. A good general rule is to prune back the canes you're keeping by half. It is also helpful to prune about 1/4" above an emerging bud that is facing outward from the center of the plant. Contrary to conventional wisdom, roses do not do best when pruned back hard to the ground unless it is to remove diseased wood. For an excellent description of how to prune hydrangeas, follow my link to www.taunton.com/finegardening/ . The only other notable plants to prune at this time are summer-blooming shrubs and sub-shrubs that bloom on new wood, such as Buddleia, Lavatera and Caryopteris.



FERTILIZING: March is a fine time to apply granular organic all-purpose fertilizers to your hardy plants. The weather will regulate their release and there is very little chance of overfertilizing if you follow the application instructions. They will feed all season and improve your soil when added to a compost mulch. Avoid all water-soluble synthetic fertilizers (ie. Miracle-Gro) until April and try to limit their use to container plantings of summer annuals. Although effective in the short-term, they often kill microbes that are vital to long-term soil health.



PLANTING: Now is a fine time to plant just about anything you can find. Make sure to dig shallow, wide holes (at least twice the diameter of the roots) and don't bury the stems of your trees and shrubs. When planting in heavy clay soils, it is helpful to add up to one part fine bark or 'bark mulch' to three parts of the native soil when backfilling around the plants to provide better drainage. The extra air space between the soil particles will prevent root-rot, the leading cause of death in heavy soils. Avoid using sand to improve drainage, it has the exact opposite effect in heavier soils. Also, avoid planting in low areas that never dry out unless you can find plants that will tolerate those conditions. If the soil is extremely dry, add one part compost to three parts of the existing soil.



WEEDING: Eliminate as many weeds as possible before they flower and go to seed. This is the key to long-term weed control. Be careful not to use dangerous preemergent herbicides like Casoron in close proximity to your plants.



SHOPPING: Spring is right around the corner and now you can enjoy the best selection of roses, hellebores, small fruits and fruit trees. There is still time to buy dahlias and lilies for summer bloom too. Over the next few weeks, nurseries will be bursting at the seams with all of their new Japanese maples, dogwoods, clematis and a huge assortment of perennials and grasses. For collectors, the rarest of the rare trees, shrubs and perennials will be coming (and going) in the next six weeks or so. Trees with the best shapes or structures will be the first to go too. If you are looking to add a special tree to a prominent spot in your garden, you may not want to wait until summer or fall. Nurseries will not receive new trees until next spring.



GARDEN TOURING: March is an excellent month to visit one of the many public or private gardens in the Seattle area. A few favorites are the Bellevue Botanical Garden, which is open to the public, and the E.B. Dunn and Elizabeth Miller Gardens in North Seattle, both of which are private gardens that you can tour by appointment.


Cheers and Happy Gardening, Tim

Slug-Resistant Hosta Varieties

Top row (left-right): 'Halcyon', 'Fire and Ice', 'Blue Angel'. Middle row (l-r): 'Sagae', H. sieboldiana 'Elegans', 'June'. Bottom row (l-r): 'Liberty', 'Sum and Substance', 'Patriot'.

Hostas are among the most beautiful and stately of foliage plants for shade gardens but many varieties are severely damaged by slugs and snails feeding on their leaves. The varieties listed above have proven to resist such damage in all parts of the U.S. and are readily available at better garden centers at a reasonable price.

All that they require is well-drained soil enriched with organic matter and regular watering through the summer months. Try to keep most hosta varieties out of the sun during the afternoon hours to avoid burning the leaves. Varieties that will tolerate sun into the early afternoon are 'June,' 'Pathfinder,' 'Sum and Substance,' and 'Great Expectations' to name a few (not all are shown above).

As an extra bit of protection against slugs, sprinkle a small amount of SLUGGO or other brand of iron phosphate pellets around the base of your hostas and other emerging perennials to prevent damage. Iron phosphate is safe to pets and wildlife and remains effective after raining. Cheers, Tim