Thursday, March 15, 2018

Diseased Resistant Flowering Dogwoods

'Appalachian Joy' at NC Arboretum, Asheville, NC
Flowering dogwood (Cornus florida) is a small spring flowering tree that typically grows 15-30 feet tall. It is generally  low-branching, and with a flat-topped canopy.

This beautiful native tree grows best in a moist well-drained soils in 3/4 day sun to light shade. Maintain a 2-4 inch mulch layer around the tree to keep roots cool and moist. It rarely requires pruning, except to remove a broken or dead limb.

Concerns about planting flowering dogwoods (Cornus florida) have calmed over the years  with the introduction of five disease resistant dogwood varieties from the University of Tennessee. Spring availability should be good and come in larger landscape sizes in containers and balled and burlapped (b&b).

Anthracnose resistant cultivar: 'Appalachian Spring'
Powdery mildew resistant cultivars: 'Appalachian Snow', 'Appalachian Blush' and 'Appalachian Mist'.

Additionally, 'Cherokee Brave', with dark pink flower bracts, has proven to exhibit exceptionally good powdery mildew resistance.

Flowering dogwood performs best in southern New England and mid-Atlantic states, eastern Mid-west states (Illinois to Ohio), and southeastern U.S.

Thursday, March 1, 2018

Best Annuals To Try in Your Garden

Canna 'Toucan' series
If you are designing your spring/summer flower garden, here are some of the very best annuals that you should shop for at garden centers. Most bloom heavily through late spring through the summer months. They are very heat tolerant and demonstrate exceptionally good disease resistance.


Alternanthera 'Purple Prince', 'Plum Dandy'
Angelonia Serena™ series 

Begonia Megawatt™ - whole color series were impressive

Begonia Whopper® series green and bronze leaf types 

Canna Toucan™ series

Canna Cannova™ series

Celosia 'Arrabona', 'Fresh Look', 'Dragon's Breath', 'Prestige Scarlet', 'Intenz'

Coleus FlameThrower™ Habernero, Salsa Verde

Hypoestes Hippo™ Rose

Impatiens New Guinea Divine™ Red, Lavender Improved, Orange 

Lantana Bandana™ series

Lantana Luscious® series

Marigold Taishan™ series Gold, Orange
Salvia 'Mystic Spires Improved'
Marigold Antigua Gold

Marigold Dune Gold, Yellow 

Marigold Moonstruck Orange, Yellow 

Marigold French Bonanza Bolero Improved, Orange, Yellow 

Ornamental Pepper Midnight Fire

Pelargonium (Geranium) Pinto series

Pentas Lucky Star™ series

Petunia Supertunia® Bubblegum, Vista Fuschia, Lovie Dovie 

Petunia Red Velour

Petunia Headliner™ Banana Cherry Swirl

Salvia Rockin'™ Playin' the Blues™
Salvia 'Mystic Spires Improved'
Scaevola Whirlwind™ series 

Thunbergia A-Peel® Lemon, Orange, Tangerine Slice 

Vinca Titan series 

Vinca Vitesse

Zinnia Profusion™ series 

Zinnia Zahara™ series

Zinnia Profusion Double™ series 
Zinnia Zahara Double™ series

Tuesday, February 20, 2018

Crocus - An Early Start To Spring

Crocus (Crocus spp.) can be your wake-up call that winter is coming to an end (USDA hardiness zones 3- 8). They bloom in late winter (in the south); fall blooming varieties are also available. Bulbs (they're actually "corms") are available in flower colors from blue, purple, white, yellow, and mixed shades.

Choose from large and small flowered types. Six petal, cup shaped flowers stand tall above the foliage which emerges as bright green blades of grass with a center white stripe. The grassy foliage grows taller after flowers wither away.

Crocus thrive in full sun and tend to bloom earlier than those planted in partial shade. They prefer a well-drained soil with pH of 6.0 - 7.0. Crocus generally fail when sown in soggy ground.

Flower buds open to warming early morning sunlight, and close up in cloudy weather and in the evening. Crocus bloom and easily naturalize where winters are cold. Sow corms in mid-fall because they require 12-15 weeks planted in cold soil (35 - 45 °F) to initiate their blooms.

Crocus grow 3- 8 inches high depending on variety. Sow drifts of crocus in several places around the garden, under trees, sprinkled in the lawn, in alpine and rock gardens, and in containers. Interplant crocus with short growing narcissus, hyacinths and tulips, and pansies and violas. Plant them where perennials emerge in mid-spring and crocus foliage has died back.

Crocus thrive in the garden for many years. Eventually, some in the planting may decline due to virus diseases which distort the leaves and cause streaking; bloom buds may fail to open. Dig up and dispose of virus infected plants to prevent spreading diseases. Crocus are generally critter-proof, but areas overpopulated by deer, chipmunks, rabbits and squirrels may dig up corms or chew down leaves and flowers. Voles also feed on corms.

The ancient Greeks collected and dried the stigmas from autumn-flowering crocus (C. sativus) to make saffron herb used in food dishes.

Crocus may be purchased at most garden centers in the fall. For a wider choice in varieties, buy from a mail order supplier like Brent and Becky's Bulbs in Gloucester, VA. They also sell fall blooming crocus.

Saturday, February 10, 2018

Growing Pentas To Attract Pollinating Bees And Butterflies

Want to attract more butterflies to your garden this summer? Pentas (Egyptian starflower) (Pentas lanceolata) is what you should be planting. Pentas are one of the best pollinator-attracting plants around. Flower colors range from red, pale lavender, pink and white. 
Pentas blooms all summer long, even during the hottest weather conditions. The large clusters of star-shaped blooms attract butterflies, bees and an occasional hummingbird. These annual flowers perform well both in garden beds and in large containers. Keep plants deadheaded and remove any spent blooms to encourage constant flowering.

Pentas plants are annuals in most U.S. climates (zone 10 hardy). The overall habit of these plants is neat and compact. If plants get too long and woody, cut them back by one-half and feed them with a water soluble fertilizer such as Miracle-Gro, Jacks™, or Schultz. Tall leggy transplants should be tipped back to develop more branching.

Overall, pentas are very easy to maintain. Newer varieties have improved disease resistance and grow shorter, e.g. more compact in habit. Pentas are troubled by few diseases and should be inspected for insects like aphids (in cool springs) and spider mites (dry hot summer periods).

Pentas prefer to be planted in full sun and in moist, well-drained soil. Pentas will dry out in hot summers and should be irrigated weekly during these times.

Leading cultivar series are Graffiti and Kaleidoscope™ (compact growers); Butterfly, Starla, and Northern Lights (taller growing).

Sunday, January 21, 2018

Winter Blooming Witchhazels

'Primervera' witchhazel at Biltmore Estates, Asheville, NC
Starting in February, hybrid witchhazels from China, Korea and Japan begin flowering. Two of the very best are a Chinese species/cultivar called H. mollis ‘Wisley Supreme’ and a hybrid form called H. x intermedia ‘Westerstede’.

'Wisley Supreme' grows to 8 - 12 feet in height and almost the same in width. Its young branches are very upright. Its pale yellow strap-like flowers are long lasting and sweet smelling upclose. Spring-summer oval leaves posess a blue - green cast, and turn buttery yellow in the fall.

Favorite cultivar 'Westerstede' is a hybrid selection (Japanese (H. japonicum) and Chinese (H. mollis) from Germany. 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 a nice buttery yellow in fall. Westerstede summer foliage possesses better leaf spot resistance than one-time favorite ‘Arnold Promise’.

Near the end of the calendar year, the U.S. native witchhazel (H. virginiana) blooms. By that time, most Americans pass by this very tall shrub/small tree with their attention set on Halloween and Thanksgiving.

Witchhazels are easy to grow in an average well-drained moist garden soil and in full sun to light shade.  A slightly acidic pH soil is preferred. Most hybrid witchhazels become tall 20 foot shrubs. Annual spring pruning is warranted to keep this vigorous shrub in check.

Most garden centers do not sell early blooming shrubs, particularly witchhazels, but plants are sold at e-nursery outlets.

Wednesday, October 18, 2017

The Garden Begonia Evolution

Whopper Rose/green leaf
'Big Red Begonia/bronze leaf

Wax begonias (Begonia x semperflorens) are popular summer annuals in flower gardens and containers. Over the last few years new interspecific hybrids have changed how we garden with wax begonias.

Hybrid begonias bloom non-stop for almost six months (mid-May thru October (USDA hardiness zones 6 and 7). Plants stand up to summer heat, humidity, and dry spells, and the foliage stays mostly pest and disease free.

Plants grow vigorously, 18 to 24 inches tall and wide by the late summer/early fall. This means fewer plants to purchase to fill the garden space which will save you money. Space hybrid begonias around 15-18 inches apart depending on which of the three series that you plant.

Hybrids boast larger and showier flowers than the traditional wax begonias. Flower size varies from 2 to 3 inches across. The brightly colored blooms are visited by many kinds of butterflies over the long bloom season. Flowers are self-cleaning and require no deadheading. Plants are compact and well-branched.

Bronze-leaf types grow best in full sun, and green leaf cultivars thrive in partial shade.

Begonias need a well-drained soil with lots of well-rotted compost added. Green leaf types tend to scorch under intense sun.

They perform best with moderate fertility and are not heavy feeders. At spring planting, feed with a slow-release fertilizer such as Osmocote™ 14-14-14 or Nutricote™ 13-13-13. Add 1 to 2 feedings in mid-summer with a water-soluble fertilizer (such as Miracle-Gro®, Schultz®, or Jacks®) southern climates (zones 6-9).

Add 2 to 3 inches of mulch for weed suppression and to conserve soil moisture. Irrigate during extreme dry spells to maintain plant vigor, and flower numbers.

Intersspecific Hybrids Begonia Cultivars:

Big™ series are available in bronze-leaf (full sun) and green leaf (part sun) forms; flower color choices are red, rose and pink.

Whopper™  series come in red and rose colors only and are available in bronze-leaf and green leaf types. Whopper plants tend to grow 20-25% larger than Big.

Megawatt™ series. Current varieties include 'Red Green Leaf', 'Pink Bronze Leaf', 'Rose Green Leaf', 'Red Bronze Leaf' and 'Rose Bronze Leaf'; new color choices will be added in 2018.

Saturday, September 16, 2017

'Bluebird' Aster A Top Coice In Mt. Cuba Evaluation Trial

Bluebird aster (Symphyotrichum leave 'Bluebird') is a top selection of U.S. native smooth aster. Bluebird was found in 1988 in a Guilford, Connecticut garden and introduced by Dr. Richard Lighty who at the time was working at Mt. Cuba Center in Greenville, DE in 1994. This tall, vase-shaped wildflower produces large 1 inch wide violet blue flowers on 3-4 feet tall stems. It has attractive, slightly glossy, blue-green foliage that is highly disease- and pest-free.

Bluebird smooth aster thrives in full sun to light shade with a broad tolerance of soil types and moisture levels. Bluebird aster will grow and bloom in part shade, but flower count will be less. In 2016 Bluebird aster was ranked as the #1 aster in an evaluation study at Mt. Cuba Center.

Spring-summer care tip: Prune off old growth from last fall and feed with 10-10-10 or equivalent granular fertilizer. Supplement with water-soluble Miracle-Gro once in mid-summer. Pinch back the young shoots in June for develop a dense plant habit and more flower buds. If left alone, the plant gets too tall and require staking in late summer as flower buds are setting up.
Bluebird aster is a great nectar source for migrating monarch and other late season butterflies.