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

Emerald Ash Borer And Others Are Spreading – Don’t Transport Firewood

Posted by Hugh on October 15th, 2012

Stack of Firewood

Moving firewood across county or state lines may also distribute serious insect pests hundreds of miles. For whatever reasons that the tree(s) were cut down in your yard, insects (including termites) may be hiding inside the logs. They may remain alive for a long time.

Over the past decade three serious exotic insect pests have been identified – emerald ash borer, Asian longhorn beetle, and walnut twig beetle. These insects continue to destroy stands of native trees in our forests and street/park trees in our urban areas. The firewood you cut down (or purchase) should not be transported miles away. Properly dispose of the wood where you live.

These three exotic pests and others are killing commercial timber acreage. Since their discovery quarantines forbidding the movement of specific wood products, such as firewood, have been established. However, the quarantine areas continue to expand every year. Legal shipping of logs via interstate highways is being checked. Camping sites, including those around major recreational or gathering areas are being inspected. This includes tailgate parties at NASCAR and football events.

Monitoring and control efforts for emerald ash borer, walnut twig beetle and other invasive pests continue. Please do your part in controlling the spread of these tree-killing pests by purchasing firewood at local campsites rather than transporting your own.

Full Moon Japanese Maple Is Very Popular

Posted by Hugh on October 13th, 2012

Fall Color on Acer japonicum 'Acontifolium'

The term “full moon Japanese maple” may be confusing. There are actually three species and cultivars of Asian maples that are referred to as “full moon”. The most popular full moon cultivar planted in the Northeast and Southern Appalachian regions (USDA zones 5 thru 7) is Acer japonicum ‘Acontifolium’.

A. j. ‘Acontifolium’ is hardy as far north as Chicago, where it requires winter protection from nearby Lake Michigan (USDA hardiness zone 5). Winter protection is crucial in zone 5, and summer heat protection is key to successfully growing it in zone 7.

A. j. ‘Acontifolium’ grows as a small 15-30 foot tree or multi-stemmed large shrub. It exhibits a spreading or mounding form. During its early years you should stake up the leader to add greater plant height. Branches tend to nod slightly.

Small clusters of reddish purple flowers appear in early to mid- spring, followed by double-winged samaras (seeds). Palmate, almost fern-like green leaves are deeply divided into 9-11 toothed and cut lobes. The circular leaves turn orange to crimson red in the fall.

The soil should be moist and compost rich, planted in full sun in the North (zones 5 -6), and in partial shade in the South (zone 7). Protect against strong winds. Japanese maples are best pruned in summer and early autumn to reduce sap bleeding.

Fertilize in late winter before growth begins with granular 10-10-10 or equivalent. Irrigate shallow rooted Japanese maples during exceptionally long dry spells.

Seven-Son Flower Is Flowering Again

Posted by Hugh on October 10th, 2012

Fall Flowering on Seven Son Flower

Back in bloom for a second time in two months! This is my way of describing seven-son flower (Heptacodium miconioides), a small 15-20 foot tree or large shrub from China.

Seven-son’s creamy white petals open in late August and finish up in early September. By late September, the petals have fallen, and the small green sepals (calyces) have expanded and turned pinkish red. Blooms are lightly fragrant if your nose is a few inches from the cluster. Numerous species of butterflies and bees are attracted to their scent.

Fall leaf color is non-existent over the drab greenish yellow heart shaped leaves in late October and November. The grayish or tan colored bark peels off in narrow strips to reveal an off-white inner wood.

Seven-son appears happiest in the north, growing in northern Ohio (USDA zone 5) as far south as Nashville, TN (zone 7). The tree does not seem to handle the rollercoaster ups and downs in winter temperatures which we commonly experience in the Southern Appalachian region (USDA zones 6 and 7). By late winter, twigs and small diameter branches become heavily cankered, leading to serious dieback in the new spring growth.

Seven-son has a rambling growth habit from stem and root suckers which necessitates annual pruning. Otherwise, it makes a good patio tree so you may enjoy its twice flowering habit.

Plant in well drained soil and irrigate when summer drought period is severe.

Don’t Forget The Sassafras

Posted by Hugh on October 7th, 2012

Sasafras Late Summer Foliage

A common woodland tree, sassafras (Sassafras albidum), aka mitten tree, is a small tree which grows 20 to 40 feet tall; some may top out at over 60 feet. Tree spread is two-thirds its height. Sassafras’ mitten shaped leaves, are easy to identify with one, two or no lobes. All three leaf shapes may be found on the same tree, as seen in the above photo.

This member of the laurel family, sassafras also has aromatic foliage. Tear apart a leaf or crush the stem; you’ll smell the famous sassafras scent. In colonial times sassafras roots and bark were important medicinal and cooking herbs. The leaves serve as larval food for swallowtail butterflies.

The tree prefers a sunny, moist, and well-drained site, and will tolerate light shade. Sassafras produces clusters of small yellow-green flowers in the spring before the leaves emerge. In late summer blue-black berries ripen, each on a red cup atop a crimson red stalk. Deer, birds and other wild fowl line up to quickly consume the fruits. Autumn leaf colors are quite variable, turning yellow, red, orange or purple.

Sassafras is vulnerable to wind or ice damage because the branches are brittle. Sassafras roots sucker prolifically and are pruned away as to not form plant colonies. When mature its reddish brown trunk is deeply furrowed.

Nurseries generally do not sell sassafras. Small container-grown plants may be purchased on-line. Sassafras has a deep fleshy taproot system and its transplant survival is low. You can also dig young plants from the wild (with owner’s permission).

Peonies Require Very Little Care Ever

Posted by Hugh on October 4th, 2012

: Lovely White Flowering Peony (P. lactiflora)

Grandma’s peonies (Paeonia lactiflora) are back in vogue. There are single- or double- flowered varieties. The single petalled types appear to Southern U.S. heat better (USDA hardiness zones 3-8). May blooming peonies come in red, pink, purple, yellow, or white colors. Depending on variety, plants grow 3 to 4 feet high and wide. Their large showy flowers attract numerous pollinating insects.

Many old–timey varieties are as popular today as they were nearly a century ago. ‘Festiva Maxima’ (double white with red splash), ‘Kansas’ (double red), ‘Raspberry Sundae’ (double light pink), ‘Sarah Bernhardt’ (double pink), and ‘Seashell’ (single pink) are some heirloom favorites.

Peonies are commonly planted as foundation shrubs because of their bushy appearance. They are long-lived perennials which take a year, sometimes two, to become established (bloom well). Shoots die back in late October and can be cut away either fall or winter.

Grow peonies in full sun and compost-rich soil. Prepare the soil deeply in advance, adding lots of peat and/or compost. Afternoon shade is recommended in zones 7-b and 8.

Fall is the best time to plant peonies. Do not crowd peonies, spacing them 3 to 4 feet apart, according to the variety planted. Set the fleshy dormant roots, being careful not to bury the eyes more than 2 inches deep. Container grown plants may be set in spring or fall.

Lay a 2 to 3 inch organic mulch around peonies, using bark chips and not wood-based mulch. Irrigate peonies during extreme dry spells. Do not splash water on the foliage and flowers; overhead watering may initiate diseases such as leaf spots and botrytis. In late winter feed with granular 10-10-10 or equivalent fertilizer before peonies emerge from the soil.

Large double flowered types tend to fall to the ground after a hard rain unless supported by a special wire “peony cage”. Place one or more wire supports above each plant soon after spring growth starts.

Peonies seldom need dividing, which is performed in the fall. Ants are not a pest on peonies and actually aid in pollinating the flowers.

If you’re shopping for either old or new P. lactiflora cultivars, check on-line at: Klehm’s Song Sparrow Nursery.

Success With Blue/Pink Mophead Hydrangeas

Posted by Hugh on October 1st, 2012

Mophead Type hydrangea in Jonesborough, TN garden

Mophead hydrangeas (Hydrangea macrophylla), the blue/pink flowering species, have been the gardening rage since the early 1990’s. Endless Summer® hydrangea started a wave of new repeat blooming (remontant) cultivars. They bloom on both new season’s as well as old wood from the previous year. These hardier cultivars extended the flowering time by 8 to 10 more weeks and bloomed in cooler climates formerly unable to grow mopheads.

To add to your success, here are additional tips on growing mopheads:

“The Right Plant In The Right Location” rule strongly applies to mopheads. The farther north you grow mopheads, the more sunlight they can handle. In USDA hardiness zones 4 thru 5-a, plant in a sunny location which receives a minimum of 6 hours of sunlight. Reduce to 4-5 hours of mostly morning sunlight in zones 6 and 7, and grow in high shade in zone 7-b to 9.

Protect Against Severe Winter Temps and Spring Freezes: Hydrangea buds openvery early. Late spring freezes frequently destroy or injure flower buds and new growth. Keep the crown (plant base) heavily mulch to mid-May in northerly areas.

Feeding: Fertilize with a slow-release fertilizer such as 10-30-10 or equivalent in early spring. For example, the phosphorus (30% P) level should be 2-3 times greater than the nitrogen (10% N) or potassium (10% K) levels. Container plants may need an extra bi-monthly feedings of a water soluble fertilizer. Over-feeding hydrangeas may result in dark green leaves (a good thing) and fewer flowers (not so good). In USDA zones 4 and 5, do not fertilize past August 15th, as it may lead to winter injury.

Watering: Mophead hydrangeas have large fleshy green leaves and insist on growing rapidly. Overwatering may lead to few or no flowers at all. On hot summer days, it is normal for mopheads to wilt for a short period in mid-day. It’s best to irrigate thoroughly once weekly, usually 1 ½ inches of water, than to water a little bit every day.

Pruning: Mopheads should not be cutback in the fall like other hydrangea species. Flower buds are borne on old wood for late spring flowering. Remember: the remontant type of hydrangeas bloom on both old and new wood.

Stunning Fall Color of Golden Larch

Posted by Hugh on September 29th, 2012

Golden Larch at NC Arboretum in Asheville, NC

Golden larch (Pseudolarix amabilis) is a rare find in U.S. landscapes. This deciduous conifer is native to eastern China. It is not a true larch (Larix spp.) and is relatively under-planted in the U.S. Golden larch appears to prosper in warm humid areas and should flourish in the southeast U.S. (USDA hardiness zone 6).

Golden larch may be planted in full sun to light shade. It thrives in organically rich moist soils which are well drained. A mature tree grows 50 to 60 feet in height and 30 to 40 feet in spread. A new tree starts out slowly, and growth becomes more moderately paced after 2 years. Tree shape is weakly pyramidal with open horizontal branches.

New spring foliage is light green, turns medium green in summer, and golden yellow in early fall before dropping. Golden larch earns its name for its spectacular golden yellow autumn leaf color, which ages to orangey-brown before falling in mid-October. Fall needle retention time is short compared to other deciduous conifers as larch (Larix spp.), bald cypress (Taxodium spp.) and dawn redwood (Metasequoia glyptostroboides). Needles range from 1 ½ to 2 ½ inches in length and are slightly curved.

Cones are 2 to 3 inches in length, 1 ½ to 2 ½ inches wide, green during the summer, maturing to golden brown in autumn. Young trees exhibit a reddish brown bark which age to grayish brown with some ridges and furrows.

Golden larch ages to a large majestic tree. Utilize it as a specimen tree on large properties such as golf courses, public parks, and college campuses. Disease and pest problems are as rare as finding this tree in U.S. commerce. Availability is from a few specialty nurseries selling on-line.

Autumn Clematis – Be Careful What You Ask For

Posted by Hugh on September 25th, 2012

Sweet Autumn Clematis on fence

SA Clematis over Holly

Autumn clematis (Clematis terniflora) is a late summer flowering twining vine with dark green foliage. The sweetly fragrant white flowers bloom for 4-5 weeks. The four petal (sepal) blossom is 1 inch across, borne in clusters, and mature into puffy plume-like seed heads. Its deciduous foliage is leathery in feel and remains mostly blemish free through the summer months.

Sweet autumn clematis grows vigorously in full to partial sunlight, easily 20 to 30 feet per year once established after its first year. It is not fussy as to soil type and does not require fertilizing ever. Irrigate only in the first year to get the vine established.

Autumn clematis comes into a garden uninvited and is capable of self-seeding and may become invasive. It can climb up and blanket a small tree or shrub as its arbor. You may thin out the vine in the spring and summer months, so the tree or shrub can access sunlight, allowing both to co-exist.

Autumn clematis has no serious disease and pest problems when properly sited in a garden. It flowers on new wood. Its vigorous growth rate suggests that you cut this clematis back hard before the start of spring. Some additional pruning may be necessary to corral its rampant growth leading up to late August flowering.

Decorate With Fall Mums

Posted by Hugh on September 21st, 2012

Beautifully Grown Fall Mum

Dendranthemums (mums) are favorite plants for outdoor decorating in the autumn season. Fall mums come in a variety of colors from white, yellow, pink, orange, red, bronze, and purple. Blooms attract numerous bees and butterflies.

Plant heights vary, depending on the degree that the greenhouse grower has sheared or sprayed (with growth retardants) the mums. As perennials, mums are reliably hardy to zone 6 (see exceptions below). Plant sizes vary from short pixies at 8 inches to tall 48 inch well-branched plants. Plant widths measure 12-36 inches across.

If you are growing mums, plants may be purchased in early spring and nurtured through the summer months. Plant them in full sun and in moist well-drained soil. Avoid planting them in areas where street and house lights will shine on them at night. Mums bloom poorly without a full night of darkness.

Feed once at spring planting time with a slow-release fertilizer. As an alternative, feed with a water-soluble fertilizer such as Miracle-Gro®, Daniels®, or Jack’s Classic® twice monthly until buds form or through the end of August.

From late spring until mid-July, pinch growing tips back 2-3 inches every two weeks. This will create well-branched plants full of blooms. Do not allow mums to bloom early in the summer, usually a reaction to severe heat or dry soil. Mums should be irrigated during dry spring – summer periods.

To perennialize fall-purchased plants, remove them from the pot and set them in the garden soil by mid-September for their pot-bound roots to knit into the soil. Mulching also helps to protect them overwinter. Do not fertilize fall-planted mums.

After a freeze has killed top growth, don’t cut back plants. Wait until late winter when buds are sprouting near the soil line. At this time you may dig up and divide the tiny plants. Discard the woody center of the crown.

Heirloom or “old-fashioned” mum varieties are back! These tend to bloom very late in the fall and are hardy in zone 5. Some of the best are:

‘Clara Curtis’ – deep pink, daisylike blooms

‘Mary Stoker’- peachy yellow blooms

‘Sheffield’ (aka ‘Sheffield Pink’) – light pink

‘Ryan’s Pink’ – bright pink daisy blooms with yellow centers.

Mums are good garden companions with fall asters and fall sunflowers (Helianthus spp.). These companion perennials require the same care, although they differ in plant heights and widths.

Emerald Spreader® Yew Exciting New Ground Cover

Posted by Hugh on September 16th, 2012

Emerald Spreader® Japanese Yew

Emerald Spreader® (Taxus x media ‘Monloo’) is a short wide-spreading Japanese yew. Emerald Spreader grows slowly, and may reach 2 ½ feet in height and 8 to 10 feet in spread over 20 years. The short 5/8 inch long, fine textured needles retain their rich dark green color through the winter months in USDA hardiness zones 6 and 7. Foliage may discolor from cold wintery winds in zones 4 and 5, unless protected.

Yews are classified as conifers and are separate sexes (“dioecious”). Female yew varieties bear green fleshy fruits called “arils” instead of cones. In early fall the green aril fruits ripen to bright red and are quite ornate in the fall-winter landscape.

Yews grow in average landscape soils and in full sun to partial shade. Good soil drainage is absolutely essential for yews. Provide adequate soil moisture during the first growing season to develop an extensive root system. Before new spring growth begins, feed with a general purpose fertilizer, such as 10-10-10.

Emerald Spreader is planted in low front borders such as home foundations or along walkways. At times branches may look rigid or stiff. Shearing 1-2 times during the growing season will soften their appearance. Do not prune yews during cold dry wintry intervals as to injure branches and needles.

Yews suffer from few insect or disease problems when properly sited. Root rots and plant deaths are common in poorly-drained soils. Yew foliage is poisonous and should not be planted if livestock are in close proximity. The seeds inside the aril fruits are also poisonous. Birds eat the fruits, but do not digest the seed. Deer and rabbits keep their distance from yews.