Tuesday, December 29, 2009

Princess Lilies -- Perennial in Zone 6

Not all alstroemerias are alike. I have been enjoying my Princess lilies (alstroemeria hybrids from Holland) over the past 6 years. They have been surprisingly winter hardy in zone 6-b where I garden. Further south in zones 7 and 8, Princess lilies prefer part sun to partial shade.

I grow'em on the east side of the garden in full sun. The harsh afternoon sun of summer is filtered through the tall shrubs and trees nearby. Mulching the soil provides extra freeze protection to roots in the winter and guarantees their return next spring.

Princess lilies need little care after planting. I feed'em a handful of granular 10-10-10 around each plant in late winter. Give them a weekly irrigation for 1/2 hour or more during summer dry spells. Plants grow short and compact and are also suitable for containers on the deck or patio.

Currently, there are 17 varieties, richly colored in whites, yellows, pinks and reds. This spring I will be adding 1 or 2 new Princess lilies to the perennial flower border .

Monday, December 28, 2009

'Sky Pencil Holly vs 'Dee Runk' Boxwood

There are few shrubs that fit into narrow spaces better than 'Dee Runk' boxwood (picture on the right). It is a better choice than currently popular cultivar 'Graham Blandy', which is seriously troubled by soil root rot diseases.

'Sky Pencil' Japanese holly (pictured above) exhibits a similar upright (fastigiate) form. Japanese holly demands a well-drained soil, and is very susceptible to several soil root rot diseases.
Both 'Dee Runk' boxwood and 'Sky Pencil' holly grow well in large landscape containers on home patios and along downtown urban streets in USDA zone 7-9. Expected height of 8-10 feet at maturity.

Wednesday, December 23, 2009

Planting Leyland Cypress May Be a "Big" Mistake

If you live in USDA Plant Zone 6-b - 7, planting leyland cypress (x Cupressocyparis leylandii) could eventually turn into a maintenance diseaster in your landscape. Leyland cypress is a green behemoth, too fast and aggressive for most folks to handle. Ask yourself, "do you really need a 60-70 foot evergreen privacy screen around your property?" If neighbors can't view in, you can't see out.
Many gardeners make the mistake of planting leyland cypress only 6-8 foot apart. Leyland demands a wider 16-18 foot spacing. Unfortunately, leyland is also susceptible to 3 fungal needle blight diseases. Diseases usually don't infect until shrubs are 10 years and older. There are no practical cures (pesticides) for these diseases. Over time the shrubs may need to be removed at a considerable cost to you.
If you must grow tall screens or hedges, I recommend the more dependable Japanese cedar (Cryptomeria japonica) or Green Giant arborvitae (Thuja x plicata). In the 20-25 foot height category, plant Nellie R. Stevens holly, Foster#2 holly and Emerald arborvitae (Thuja occidentalis 'Smaragd').
Some great evergreen choices in the 10-15 foot range are leatherleaf viburnum (Viburnum rhytidophyllum), skip laurel (Prunus laurocerasus 'Schipkaensis') and 'Hick's Yew (Taxus x media 'Hicksii').

Sunday, December 20, 2009

Beware of Storm Damaged Trees

This past weekend Northeast Tennessee as well as most of the coastal eastern U.S. was hit by heavy snow, 7 inches and more of heavy, wet clinging snow. Many of my neighbors lost electric power, telephone and cable.
A driveby survey of tree damage around the neighborhood found that the following tree species suffered the most breakage (in order of severity):

  • Chinese (Siberian) elm
  • Silver maple
  • White pine
  • Weeping cherry (pictured)
  • Topped trees
  • Bradford (callery) pear
  • Red maple
  • Dead or dying trees
  • Sycamore (London planetree)
  • Southern magnolia
  • Sweetbay magnolia
  • Yoshino cherry
  • Dogwood
The type of injury ranged from large falling limbs two inches or more in diameter (Chinese elm, white pine, and silver and red maples) to many small branches less than one inch diameter (weeping cherry. magnolias and dogwoods).

Lessons learned:

  1. Select a tree species that is reliably storm resistant. Expect some limb breakage on any tree species, but fast growing trees like Chinese elms and silver and red maples, and those that are not properly maintained, suffer the most damage. When homeowners properly prune landscape trees every 5 years, storm damage is considerably less.
  2. Old mature trees, which have outlived their expected life span, should be removed and replanted with younger specimens. For example, Chinese elm, silver maple and white pine reach full maturity within 40 years. Bradford pear has a short replacement time of 15 years. Pruning maintenance on all landscape trees should be every 5-7 years.
  3. Topped trees suffered considerable limb losses as the weakened re-growth is exceptionally susceptible to breakage. The topping of trees is never a recommended practice. In my opinion, if a large tree threatens your home, personal property or utility lines, either seek care advice from a professional arborist or have the tree removed by a licensed and bonded arborist.
  4. Previously dead or dying trees pose a bigger hazard during in a storm.

Friday, December 18, 2009

Smiling Pansy Faces

Success in blooming pansies and violas in the winter season depends on two key factors: date of fall planting and soil nutrition. If you live in USDA plant zone 6, pansies must be planted by October 15th, two weeks earlier in northerly zone 5, or two weeks later in zone 7. Early fall planting promotes faster and deeper rooting of plants before the cold weather arrives.

Pansies need feeding bi-monthly with 10-10-10 or equivalent fertilizer to achieve maximum bloom potential. Either organic-based or slow release fertilizers are good nutrition sources.

Other pansy ideas:

Offer plants a weekly drink of water if rainfall in your gardening area is low.

In the fall consider interplanting tulip or hyacinth bulbs among the pansies or violas.

Warm weather in mid-May will stretch pansies plants and look "worn out". It is time to plant summer annuals. Remove pansies and add them to the compost pile. Add finished compost to the flower bed before digging in summer annuals.

Baptisia - 2010 Perennial Plant of the Year

Baptisia (Baptisia spp.) is a long lived, low maintenance perennial. This American native thrives in rich well-drained soil under plenty of sunlight. Treat the roots as fragile and permit baptisia one year to establish itself. It will reward you for many years ahead.

Modern day cultivars are usually hybrids. Lovely spikes of purple (B. australis), lavender blue (B. minor), white (B. alba), bright yellow (B. sphaerocarpa) and bicolors appear in May or June and each species blooms for 4-5 weeks. Its blue-gray foliage and sturdy upright shrubby form are assets in the summer garden.

Baptisia is heat and drought tolerant and almost invincible to diseases and insects. Plants grown in partial shade may appear stretched or leggy, requiring some staking. Few flower spikes are produced in shady areas.

Surprise lily (Lycorus)

Surprise lily or resurrection flower (Lycorus radiata) should be ordered in January because of limited available supply. Divisions are shipped fresh dug in June for immediate planting. Flowers emerge in late July and August. Lycorus is long-lived garden perennials, hardy in USDA hardiness zones 6-b thru 9. In the past I have ordered mine from Brent and Becky's Bulbs on-line.

Dogwoods for Spring

More available in 2010 are 5 new disease resistant dogwood varieties from the University of Tennessee. Supply should be better than in past years, but order from your local garden center early before the spring sales rush.

Powdery mildew resistant varieties: 'Appalachian Snow' (pictured), 'Appalachian Blush' and 'Appalachian Mist'

Anthracnose resistant variety: 'Appalachian Spring'

Poet's laurel-great shade garden shrub

Alexandrian laurel or poet’s laurel (Danae racemosa) is a lovely 2-4 foot, low arching, evergreen shrub. It thrives in shady areas of the garden, spreading slowly from root suckers. Poet’s laurel stays in its intended place and does not overwhelm other plants around it. Tiny greenish-white flowers appear in late spring and are often overlooked. By early fall the ½- inch round berries turn bright orange-red and persist to year’s end. Poet’s laurel prefers a moist well-drained soil in the shade garden. You can cut its glossy waxy-green foliage for indoor floral arrangements.