What Grows There :: Hugh Conlon, Horticulturalist, Garden Advisor, and Photographer

Blueberries

Posted by Hugh on March 12th, 2011

Blueberries (Vaccinium spp.) are healthy for you and exceptionally easy to grow organically (without pesticides). Why?- because blueberries are bothered by very few disease and insect problems. Success in growing blueberries depends upon pre-plant soil preparation. If you’re thinking about growing blueberrues for the first time, then allot this calendar year for soil preparation. Put off planting blueberries until the early fall or next spring. Good bed prep includes:

soil pH of 4.8-5.2 -achieved by an application of elemental sulfur plus acidic organic matter sources such as peat moss and old sawdust
raising and maintaining an organic level of 3% (and higher) incorporating composted leavs and yard clippings, old sawdust and peat moss

Good garden prep takes 12-18 months, so plan ahead. Add another two years for plants to become established and ready for picking. Spacings between plants are 5-6 feet apart for rabbiteye and 4-5 feet for highbush. For large plantings, allow 10-12 feet between rows for mowing, pruning, picking and other maintenance.

Recommended varieties for the Southern Appalachian region (USDA zones 6 and 7):

Highbush: ready for picking from mid-June for 4-6 weeks, cross-pollination not required but recommended. Duke is highly recommended, an early, big berry, excellent quality, and does not tend to overbear. Others are Bluecrop, Echota, Blue Ridge, Berkeley, Jersey.

Rabbiteye: ready in mid-July for 6-8 weeks, cross-pollination with 2-3 varieties is required. Plant Tifblue, Climax, Powder Blue, Centurion, among others.

Act Now for Crabgrass-free Lawn This Summer

Posted by Hugh on March 9th, 2011

What grows there? Hopefully, it’s not crabgrass this summer. Crabgrass (Digitaria spp.) is an annual weed grass that devour lawns, shrub beds and flower gardens. There are lots of effective crabgrass preventatives sold at garden shops, hardware stores, and farm supply centers.

There are numerous trademarked products. It is important to read and understand package instructions. The principal product tradenames (and active ingredients) are:

Barricade® (prodiamine)

Dimension® (dithiopyr)

Echelon® (prodiamine + sulfentrazone)

Pendulum® (pendimethalin)

Ronstar® (oxadiazon)

All products should not be used on newly seeded, sodded or sprigged lawns. In addition several store brands (not listed here) may contain the same or a different active ingredient.

Pre-emergent crabgrass control is your best option. Apply the herbicide in late winter to early spring before the crabgrass seed germinates.

Rather than choosing a calendar date as an application deadline, use forsythia, a common spring flowering shrub, for your timing guideline. If 80 % of forsythia flowers have dropped, expectations for good crabgrass control falls off if a pre-emergent preventative has not been applied.

These products provide 85% effective crabgrass control up to 100 days after application. A second application is required in late spring or early summer for a crabgrass free summer.

One additional tip is to irrigate after applying the herbicide, an equivalent of 1/2 inch of rainfall.

Pulmonarias: Wonderful In The Shade Garden

Posted by Hugh on March 6th, 2011

Although my multi-year addiction for hostas has never waned, I remain equally passionate about the lungworts (Pulmonaria spp.). Lungwort is also called Bethlehem sage and Jerusalem sage. Their uniquely splotched or variegated foliage wakes up a dark patch in any shade garden.

Lungworts are planted as ground covers and for color accents. In early spring (March), lungworts send up small lovely bouquets of small tubular flowers. Flower colors, depending on variety, range from white, lilac, pink and blue.

Lungworts are vigorous and long lived. Several are semi-evergreen in garden zone 6 and deciduous in zone 5. Their culture is almost identical to hosta. Grow them in compost-rich soil and keep plants mulched and moist in the summer months. Lungworts benefit from division every 4-5 years.

Pest problems are rare, although some cultivars may be susceptible to mildew. The species P. longifolia and hybrids thereof, with long narrow or lance-shaped leaves, are most adaptable to gardens in the Southern Appalachian region (USDA zones 6 and 7). They’re more resistant to mildew diseases and high temperature dieback. Occasionally, snails and slugs are problem pests.

Suggested companion plants include ferns, small leaved hostas, bluebells (Mertensia), coralbells (Heuchera spp.), foamflowers (Tiarella spp.), dwarf variegated Solomon seal (Polygonatum spp.), and lenten rose (Helleborus spp.).

Prune Some Hydrangeas Now

Posted by Hugh on March 3rd, 2011

Hydrangea paniculata 'Limelight' in July

PeeGee or panicled hydrangea (Hydrangea paniculata) and our native Smooth hydrangea (Hydrangea arborescens) are pruned now in late winter thru early spring. Why? – because these hydrangeas bloom on new or current season’s wood.

Over the years these two hydrangea species grow to enormous sizes. When they overwhelm their garden space, severely cut them back to within 6 -12 inches from the ground in late winter or early spring. Next, thin out the number of shoots (canes), leaving several of pencil size thickness. In the spring each cane will grow out new shoots which bloom this summer.

Severe cutting back is called renewal pruning. Timing will vary with the species of hydrangeas planted in your garden. After pruning apply a slow release fertilizer especially formulated for flowering shrubs. Follow the package directions. Apply a good organic mulch to a 2 – 3 inch depth around each hydrangea to conserve soil moisture this summer.

Oakleaf (H. quercifolia) and bigleaf (H. macrophylla) hydrangeas may also be pruned now, but flower numbers in spring and summer may be greatly reduced.

Winter Jasmine Rising

Posted by Hugh on March 1st, 2011

Retaining wall of winter jasmine

Is the worst of winter behind us? Winter jasmine (Jasminum nudiflorum) is often confused with forsythia shrubs which bloom 3-4 weeks later in the spring. This hardy winter blooming vine from China frequently blooms in late February and March when daytime temperatures climb into the mid-50s for a week or more. Evening chilling temps down into the low 20’s don’t seem to injure the flowers.

This vine thrives in many parts of the mid-Atlantic and southeastern U.S. (USDA hardiness zones 6 -8) in full sun to partial shade. Its dark green tri-foliate leaves are semi-evergreen in zone 6. New foliage emerges in April after flowering has ended.

Hundreds of bright yellow 1 ½ inch tubular flowers are lightly fragrant, originating along a thick network of green stems. Winter jasmine is a very aggressive grower and is often utilized for soil retention on steep banks or to cover over an unsightly retaining wall or fence. Some gardeners grow it as a low 3-4 foot tall shrubby mound, 4-5-6 feet wide.

Winter jasmine grows in almost any soil, and demonstrates good drought tolerance once established after two years. Every 3 or 4 years rejuvenate winter jasmine by cutting back vines severely immediately after flowering.

Prune as needed in early spring just after flowering has finished. If planting starts to look scraggly, cut back hard to 12-18 inches and feed generously with 10-10-10 or equivalent fertilizer.

‘Kintoki’ Japanese Cornel Is Perfect Fit for Small Urban Gardens

Posted by Hugh on February 27th, 2011

: ‘Kintoki’ summer foliage

It’s a dogwood and comes close to being a plant that offers four seasons of landsape beauty. Kintoki Japanese cornel (Cornus officinalis ‘Kintoki’) is a special semi-dwarf 10-12 foot tall dogwood which fits into most small gardens. Kintoki’s bright yellow flowers open in early March in the Southern Appalachian region (USDA zones 6 and 7).

Bloom season is almost 4- weeks long, and begins 3 – 4 weeks ahead of forsythia. A frigid winter’s evening does not hurt the blooms. The foliage exhibits a dark green polished finish and purplish fall foliage color does not occur is not until late November.

Japanese cornel grows in most soils as long as the drainage is good. Plant in a full sun to partial shade location where it’s easily visible from inside your home. When in bloom, March weather is often wild and changeable and gardeners can remain warmly huddled indoors.

In the fall attractive Kintoki’s multi-colored bark and bright edible drupe fruits offer autumn thru winter interest for humans, birds and other wildlife. Over the next 2-3 years, availability of Kintoki is likely to be limited to specialty nurseries selling in the internet marketplace.

‘Sunsphere’ Japanese Cornel

Posted by Hugh on February 24th, 2011

'Sunsphere' Japanese Cornel

Japanese cornel (Cornus officinalis) is a tall shrub or small tree dogwood which matures to 20-25 feet in height and 15 feet in width. ‘Sunsphere’ Japanese cornel was discovered by Mike Stansberry, owner of Beaver Creek Nursery in Knoxville, TN.

Japanese cornel is the official start of spring in my garden, even though the calendar reads late February. This cultivar is a heavy bloomer, the bright yellow flowers about 7-10 days before other Japanese cornels. Flowers are rarely injured by low night temperatures still common across the Southern Appalachian region (USDA zones 6 and 7) in late February and March.

Japanese cornel grows in any average well-drained soil in full sun to partial shade. Spring-summer foliage is dark green, and autumn colors varing from light yellow to reddish purple before falling. As the grayish outer bark ages, it chips off in tiny strips, exposing the yellow-orange inner wood. In late summer the cherry red drupe fruits have colored up and are consumed by hungry birds.

Sunsphere is available thru internet purchase or stop by Beaver Creek Nursery in Knoxville, TN.

Next up: ‘Kintoki’ Japanese cornel features lovely summer-fall glossy foliage

Edgeworthia Deserves A Try

Posted by Hugh on February 21st, 2011

: Edgeworthia flowering in March garden

First, I must thank South Carolina nurseryman, Mr. Ted Stephens, who gifted me a Chinese paperbush (Edgeworthia chrysantha) nearly 6 years ago. Most plant authorities rate its winter hardiness to USDA zones 7 and 8. It struggled through its first winter and spring in my zone 6-b garden, but has never disappointed. A few gardeners living near me are also enjoying some success.

Paperbush is not difficult to grow and is fascinating to watch as cold temperatures moderate in early March. The uniquely nodding floral buds are clearly visible on branch tips in early fall. Fragrant flowers open in early March before the new spring foliage emerges. The tubular clusters of flowers are light yellow on the inside and white on the outside. After a number of years roots will sucker new plants, forming a small plant colony. If your plant reaches suckering stage, congratulations, it is happy in your garden.

Its greenish blue foliage is attractive over the 4-5 feet tall plants. Paperbush is a multi-stemmed shrub. The new growth is coated with fur-like reddish brown hairs. Paperbush belongs in a protected woodland environment under partial shade in the summer. Its unusual flowering and early season flowering entice plant collectors to give it a try.

Paperbush is definitely a collector’s plant and is available at e-commerce nurseries.

Revitalize Pansies Now

Posted by Hugh on February 18th, 2011

Across many areas of the Southern Appalachian region (USDA zones 6 and 7) snowfall has been plentiful this winter, but total rainfall is below normal. It takes 10 inches of snow to equal one inch of rainfall.

Fall planted pansies and violas are now both hungry and thirsty. Provide them with a shot of fertilizer and water. Winter feeding will not injure these hardy plants.

Apply an agricultural grade of fertilizer such as 19-19-19 or equivalent. Do not use a slow release granular product this time of year as the fertilizer prills do not release their nutrient charge in cold soils. Any water soluble fertilizer, including Miracle Gro® or Jacks® brands, are also good choices for feeding pansies and violas. Follow package directions.

Irrigate thoroughly after feeding to wash the nutrients into the soil as well as to re-hydrate plants. Watering also prevents the fertilizer salts from burning the plant foliage.

Withis a few days your listless pansies should perk up during this warm weather spell which we are currently enjoying.

Opening Show in February- The Witchhazels

Posted by Hugh on February 15th, 2011

Chinese witchhazel (Hamamelis)

First, not to confuse you, our North American native witchhazel (Hamamelis virginiana) blooms in the fall. Our native vernal witchhazel (H. vernalis) has been flowering for the past few weeks.

In February, the showiest witchhazels are opening now – species from China, Korea and Japan. Two of the very best are a Chinese species/cultivar called H. mollis ‘Wisley Supreme’ and a hybrid form called H. x intermedia ‘Westerstede’. Both are hardy in the Southern Appalachian region (USDA zones 6 and 7).

Let’s begin with Wisley Supreme. This vigorous shrub grows to 8 – 12 feet in height and 10 – 12 feet in width. A young shrub branches upright and with age takes on a spreading habit. Its pale yellow strap-like flowers are long lasting and sweetly scented. Spring-summer oval leaves exhibit a bluish green cast, turning buttery yellow in the fall.

Westerstede is a hybrid witchhazel from Germany (Japanese (H. japonicum) and Chinese (H. mollis). Westerstede bears light yellow 1- inch long ribbon-like flowers which are fragrant. Floral buds begin to open 1 – 2 weeks later than Wisley Supreme. The broad 5 – 6 inch circular green leaves turn buttery yellow in the fall.

While most hybrid witchhazels grow to tall 20 foot shrubs, the mature heights and widths of Westerstede and Wisley Supreme are similar. Westerstede summer foliage possesses better leaf spot resistant than the old-timey favorite ‘Arnold Promise’.

Witchhazels are easy to grow in an average well-drained moist garden soil. A slightly acidic pH soil is preferred. Annual spring pruning keep the vigorous witchhazels within their assigned garden spot.

Since most garden centers do not sell early blooming shrubs, witchhazels are easily purchased from the internet nursery market.