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

American Holly For Year-round Interest

Posted by Hugh on December 22nd, 2015

Century old Ilex opaca at Biltmore Estate, Asheville, NC

American Holly (Ilex opaca) is a pyramidal evergreen tree that deserves to be planted more for multiple reasons. It is native to the eastern and central U. S. and is easily identified by its spiny green leaves (USDA hardiness zones 5 to 9).

It grows slowly to 15 to 35 feet, sometimes taller. The leathery, deep green leaves (2-4 inches long) are spiny-tipped along the leaf margins. Hollies are dioecious, e.g. individual plants are sexed either male or female.

Greenish-white flowers appear in May-June. Bright red or golden yellow ¼ – ½ inches diameter drupe fruits (“berries”) ripen on female trees in fall and persist on the tree through winter. For good fruit set male and female hollies needed to be planted within ½ mile apart.

American holly grows in any average soil, but fails in poorly drained or soils that periodically flood. In northern zone holly grows in full day sun and prefers partial afternoon shade in southern region (7b -9). In early spring feed a slow-release fertilizer specifically labelled for acidic loving plants.

Holly foliage and berries are used for winter holiday wreaths and other decorations. The tree provides shelter for birds from harsh weather and predators; holly berries are a steady food source all winter long. Spiny leaves contain toxic sap and are an adequate deterrent against deer.

American hollies are susceptible to leaf drop, leaf scorch and chlorosis (leaf yellowing in high pH soils). When properly sited, hollies have few disease and insect problems. Otherwise, the list of potential problems grows long.

Utilize as a single tree specimen or group several for foundation planting and for hedging. Foliage and fruits are superior winter features.

Over 100 cultivars of American hollies are identified and cataloged. Five exceptional cultivars are:

‘Dan Fenton’– broad pyramidal form to 25 feet high; dark green leaves and shiny red berries.

‘Jersey Princess’– female pyramidal form with glossy dark green leaves, and bright red berries released from Rutgers University.

‘Jersey Knight’– male pollinator for ‘Jersey Princess’ with dark green leaves (another Rutgers introduction).

‘Satyr Hill’– vigorous grower, upright pyramidal habit, olive green foliage, and bright red berries.

‘Xanthocarpa’– pyramidal form and yellow-orange berry fruits.

Growing Calamondin Orange

Posted by Hugh on December 18th, 2015

Calamondin orange (Citrofortunella mitis)

Calamondin (Citrofortunella mitis) hails from China and is hardy to 20 ºF in temperate regions. It prospers outdoors in Florida, central and southern Texas, and Southern California gardens. Its sweetly fragrant flowers develop into edible ornamental fruits beginning in late fall. Small 1-2 inch diameter orange fruits are highly decorative as an indoor house plant.

Calamondin can be grown in a large tub or portable container plant in colder regions where do not commonly grow. It thrives in bright light near a window for best growth and fruiting, but will tolerate lower light levels in winter. It is the most popular potted citrus, along with Meyer lemon and Ponderosa lemon. It performs well as a summer patio plant; it may be trimmed as a hedge in warm zone 8 and further south.

Water plants as needed; excess or lack of water will kill calamondin. Repot your plant in mid- to late winter. Add a slow-release fertilizer such as Osmocote™ to the container in early spring and continue fertilizing with full strength water-soluble acidic fertilizer (Miracle Gro™ or Peters® 20-10-20 or Schultz®) monthly over the summer and early fall. Fertilize sparingly during the winter months using one-half strength water-soluble fertilizer every 4-5 weeks.

Calamondin may bloom 4-5 times a year. The spring growth flush often produces the most flowers. The flowers are self-fertile and require no cross-pollination. Flower and fruit often will appear at the same time. Calamondin fruits take nearly a year to ripen.

Fruits are thin skinned and have short keeping life of 1-2 weeks after picking. If you eat the fruit, choose firm yellow to yellow-orange fruits. Use pruners or scissors to harvest off the tree instead of pulling them. Prune calamondin in late winter before the spring growth flush. Most cuts are for shaping and size control. Remove dead or damaged twigs at any time.

Plants should be inspected for mites, mealy bugs, scales, and aphids every few weeks; particularly check the underside of leaves. Insecticidal soaps and neem oil are effective in managing pest outbreaks.

Re-blooming Your Poinsettia

Posted by Hugh on December 14th, 2015

Poinsettias for Sale

Many people like to save their poinsettia plant and re-flowered it next Christmas. Scheduling a poinsettia to re-bloom is not difficult, but you need to follow an exact year-long procedure. First, continue to water the soil in the pot until early April.

In April, cut the stems back to about 4 inches above the soil. Replant into a new container that is 1 to 2 inches larger in diameter, adding new soilless potting mix. Many good commercial potting mixes are available. Do not use soil from the garden as it may contain diseases. Water the soil thoroughly when the surface of the soil feels dry to the touch. Place the plant near a sunny window (east or southern exposure is ideal) and at temperatures between 65 – 75°F.

New shoots will appear within a few weeks. Start to fertilize every 2-3 weeks with a water soluble fertilizer such as Miracle-Gro™, Peters™, or Schultz™ according to package directions.

By mid-to late-May (if danger of frost in your area is low), move poinsettia outdoors in a lightly shaded location, such as under a shade tree for the summer. You may wish to submerge the pot in a hole so that it does not fall over on windy days. Continue watering and fertilizing the plant as needed through the summer.

Starting in early July, lightly pinch each stem (remove 1 inch of shoot tip) to encourage branching. In late August, add a second pinch, leaving 3-4 leaves on each shoot. After this second pinch, bring the plant indoors (or late September), and place it in a sunny window. Keep the plant at a temperature of 65 to 70°F at night and continue watering and fertilizing.

Poinsettias are short-day plants, e.g. they initiate flowers about 10 weeks after daylength shortens to 12 hours or less. This part requires your complete dedication: keep the plant in complete darkness between 5 p.m. and 8 a.m. from early October until Thanksgiving Day for a total of 6 weeks. During this interval, any kind of light exposure between 5 p.m. and 8 a.m. will delay flowering. Putting plant in a closet or covering with a black sheet are two popular options. Over the daytime hours move the plant near a sunny window and continue watering and fertilizing your poinsettia.

Happy Holidays!

Unique Life Cycle Of Bumble Bees

Posted by Hugh on December 13th, 2015

Bumble Bee pollinating

Bumblebee pollinating buddleia

Bumble bees (Bombus spp.) are highly beneficial insects that pollinate native wildflowers, fruits, vegetables, and many agricultural crops. They’re large robust insects with an easily identifiable black and yellow hairy abdomen. Hundreds of branched hairs pick up and transfer pollen from flowers. About 50 species of bumble bees inhabit North America.

They share some common traits with honey bees, which are not native. Both are highly social insects and live in colonies with one queen and many workers. Bumble bee colonies last less than one year compared to honey bees. They do not store a surplus of honey for harvested. Populations fluctuate from year to the next, subject to environmental factors, parasites and predators.

Bumble bees are ground nesters, making their colonies in mostly underground holes or a few above ground partly covered by debris. Their nests are larger than those of solitary bees. In early spring a young queen finds an abandoned nest or burrow made by another critter and prepares it for her brood. She builds a few wax pots that she fills up with pollen and honey, and a larger cell for her brood. She lays her eggs, laying no more than half a dozen at first. These eldest offspring are all sterile female workers. Once this brood is fully grown, the queen rarely leaves the nest again and spends all her time laying more eggs while the workers take care of all the activities in and out of the nest.

By midsummer the colony (nest) grows rapidly and will have 20-100 workers. Near summer’s end, the queen lays eggs containing fertile males and females. The females emerge from the nest and mate with males. All sterile workers, male bumble bees, and queen mother die at the end of summer. A mated queen hibernates 2-5 inches deep in the soil over winter and re-emerges found a new nest.

In some countries bumble bees are imported to pollinate specific crops such as forage clover (Trifolium pratense) in fields and tomato crops in greenhouses. They can fly at much lower temperatures than honeybees and can pollinate flowers with long, narrow corollas.

Source: several USDA publications on Bumble bees

What’s In Your Garden Soil

Posted by Hugh on December 10th, 2015

Tilled Garden Bed

Choice of 10-10-10 or 6-12-12 Blended Fertilizer at this garden center

There are two basic rules in gardening:

1. the right plant in the right place, and

2. properly feeding the soil that nourishes the plants.

Many problems in lawns and gardens can be avoided if the gardener knows what the fertility and pH of the soil is.

What is soil pH? It is a measure of the soil acidity or alkalinity. A pH meter will accurately measure this. Soil pH range varies from 0 – 7 – 14. Readings from 0 to 7.0 are acidic, 7.0 is neutral, and above 7.0 is alkaline. Most (not all) garden flowers, vegetables, and landscape plants (shrubs, trees and vines) grow best in the mild acidic range between 6.0 and 7.0. Outside this pH range, some minor nutrients like iron (Fe) and manganese (Mn) may become unavailable above 7.0 or in over supply below 5.0.

Soil tests are available from a number of sources: DIY kits sold at garden centers, on-line, or through mail order sources. The results obtained from these test kits are “ball park”. Soil testing from university soil labs or private labs is more accurate. For information about soil testing from university soil labs, contact your local Extension office in your state or county. For an extra fee, the lab may also determine your soil type: sand, silt, or clay.

Results from a soil lab should list: soil pH and suggest amounts of fertilizers and lime to apply to each area of your garden. Blended fertilizers contain nitrogen (N), phosphorus (P), and potassium (K). The analysis may suggest adding only nitrogen. Lawns may benefit from extra calcium and/or magnesium by liming. Dolomitic limestone (Dolomite) contains magnesium (Mg) and hydrated lime supplies calcium (Ca). If you need to lower soil pH, say for growing blueberries or azaleas, how much sulfur (S) should you apply per 1000 square feet.

Frequently, autumn through mid-winter period is the best time to test rather that in the spring. Labs are very busy at that time and a report may take 4-6 weeks to process.

Widely Planted Norway Spruce

Posted by Hugh on December 7th, 2015

Norway spruce (Picea abies)

Norway Spruce cones

Norway spruce (Picea abies) is a large pyramidal evergreen conifer. It is native to the mountains of northern and central Europe where it often matures to 100 feet or more in height. In the cool temperate areas of the U.S. and Canada, Norway spruce is widely planted, typically reaching 50 to 80 feet tall at maturity (USDA hardiness zones 2 to 7-a).

Norway spruce prefers a moist, mildly acidic, well-drained soil and in full sun. The species thrives in the mountains of northeast Tennessee and southwest North Carolina (zone 6 and 7-a), but fails in middle TN and eastern NC (7-b).

Annual growth rate is rapid. Main branches are turned slightly upright on the ends and secondary branches are drooping (pendulous), more apparent on mature trees. Branches are clad with four-sided medium green needles that are spirally arranged along branches. Needles are soft to grip. It is often mistaken for Colorado spruce (P. pungens), whose bluish green needles are right angled and sharp to the touch. Cylindrical seed bearing cones, 5 – 9 inches long, are pendulous. Sticky resin frequently coats the bark of trunk and main branches.

Norway spruce is not troubled by serious insect or disease problems when properly sited. Several species of mites may plague individual spruce trees from time to time. Deer usually stay away from most needle conifers. Birds make use of the layered branches for shelter from wind and cold and as a haven from predators.

Norway spruce is commonly planted in parks, large properties, and woodland areas. It is also utilized as a tall privacy screen, windbreak, or for erosion control. As many as 150 tree and shrub cultivars of Norway spruce are available. Dwarf, upright and weeping forms are set before building foundations and rock garden plantings. It is used as a cut Christmas tree, but needle retention is short-lived.

Mature sspruce at Biltmore Estate, Asheville, NC

Mature spruce at Biltmore Estate, Asheville, NC

Care Of Staghorn Ferns

Posted by Hugh on December 4th, 2015

Staghorn fern hanging basket in shade tree

Staghorn fern (Platycerium bifercatum) is an epiphyte from the forests of Africa, Australia, and Southeast Asia. In temperate regions, it is a popular house plant. In their natural habitat, it prefers to grow attached to tree trunks or rock outcroppings for support. It draws no nutrients from the tree.

Two very different types of fronds (leaves) are found on the same plant. The foliar leaves are fertile, able to bear spores, and resemble the antlers of a deer and elk. The basal leaves, called “elephant ears”, attach to a rough textured surface such as a bark slab or cement wall for vertical support.

Annual care is minimal. Staghorn fern thrives outdoors in the warm humid summer air in the shade. In late spring, when danger of frost has passed, mount or hang fern in indirect sun (preferably early morning sun) and protect it from high winds. Room temperature range between 65 – 75 °F is ideal and staghorn fern can tolerate as low as 25 °F. Keep it drier over the winter period. Never overwater as this often results in fungal disease problems.

It can be grown in a pot or hanging basket in a porous gravelly soil. The upright foliar fronds collect water and debris (dead or decayed leaves) which nourishes the plant. Grow in filtered, not direct sunlight. It attracts very few pests, but do inspect fronds periodically for mealy bugs and scale.

The fertile green fronds may turn gray or silver colored when spores are present. Brown patches on the tips of older fronds indicate mature spores are present.

As the fern matures, it may become too large and heavy. Senior gardeners will opt to pass along this long-lived “family fern” as part of their estate.

Training to vertical support: Create a bed or nest containing water-saturated sphagnum moss or osmunda fiber. Plant staghorn fern and secure with thin wire or twist ties to the bark support. Pound some nails into a bark slab to create the nest containing potting media (sphagnum moss). Keep the moss moist and eventually new fronds will appear.

Buying/Planting A Live Christmas Tree

Posted by Hugh on December 1st, 2015

Colorado spruce, formerly a Christmas tree, now landscape tree

Colorado spruce, formerly Christmas tree, now a landscape tree

Cut Fraser Fir Trees for sale

A living Christmas tree—one that’s planted outdoors after the holidays—has become a tradition with many families to commemorate a birth or someone’s passing.

Purchase a live Christmas tree and plant it in your landscape after the holidays. Pre-dig a planting hole ahead because outdoor weather may not be suitable for digging. For safety sake, fill it with leaves or mulch to prevent freezing or cover it with a board or piece of plywood so no one accidentally falls into it.

Choose an evergreen species that grows well in your plant zone. Your choice includes eastern red cedar, white pine, Norway spruce, and Colorado blue spruce. Frasier fir (Abies frasieri), a very popular Christmas tree, prefers a cool mountain location above 3500 feet elevation (USDA hardiness zones 4-7) and will not be a good landscape tree. Over the past quarter century Leyland cypress has become a popular choice in warm parts of the Southeastern U.S.

Here are some planting steps:

Examine the rootball and top (leader) before you purchase. Rootball for a 6-7 foot tree should measure 30 inches or more in diameter, tied, and wrapped tightly in cloth burlap.
Dig a shallow hole twice the diameter of the rootball.
Unload the tree and be careful not to damage the rootball.
Place the rootball in a tub or container large enough to snugly support it.
Water rootball if it feels dry to the touch; do not let tree stand in water.
Tree should not stay indoors for more than 10 days.
Use LED lights which emit little heat and are energy efficient.
Inspect rootball moisture every 3 days.
Move tree to an unheated garage or basement until you’re ready to plant outside.
Plant outdoors in prepared hole, water and add 3 inches of an organic mulch around tree.

Stop Inviting Critters to Your Property

Posted by Hugh on November 27th, 2015

Haven for Unwanted Critters?

Landscaping practices can influence pest populations. Old landscape timbers, particularly those that are partially rotted, may provide food for termites. powder post beetles, and carpenter ants. Numbers of millipedes, earwigs, crickets, sowbugs, and clover mite larvae may be greatly reduced if piled up old branches and boards are properly disposed of.

Mosquito populations rise in wet summer weather when buckets, plugged up eaves, old tires lay around filled with stale rainwater. Mosquitos carry serious health risks such as the West Nile virus and malaria.

Never distribute organic based mulches near house wood siding and low window sills. Watch wood chip mulch and other wood products on or in the soil (lumber scraps, boards, firewood, pallets, etc.) for signs of activity if termites are present in your area. Keep wood-based mulches several inches away from the house foundation. Bark-based mulches are permitted. Never allow soil or mulch to contact wood- made windowsills or house siding. Periodically inspect mulched zones around your home and garage for signs of termite activity.

Remove old fallen branches to discourage rodents and snakes from nesting. Firewood can also harbor large cockroaches, carpenter ants, wood-boring beetles, termites and others. Clean leaves and debris from gutters.

Overgrown weeds and grasses on abandon properties and vacant lots become the major weeds in the entire neighborhood. Noxious weeds gain a foothold in residential areas by one neighbor who does not take ordinary care of his or her property. In a short time invasive plant species such as multiflora roses, ivies (adult forms), honeysuckles, Johnson grass, and thistles cost muncipalities tens of thousands of dollars to eradicate.

Stop Destroying Forsythias

Posted by Hugh on November 24th, 2015

Forsythia 'Gold Tide' at NC Arboretum In Asheville, NC

Forsythia ‘Gold Tide’ in summer at NC Arboretum in Asheville, NC

Large Forsythia x intermedia needs annual pruning

Forsythia (Forsythia spp.), also called “yellow bells”, is an extremely popular spring flowering shrub (USDA hardiness zones 5-8). Their bright yellow flowers signal the coming of spring. However, many gardeners do not know how to prune them.

Tall 8-12 foot forms of F. x intermedia are commonly sold at most U.S. garden centers. Forsythias grow from 2 to 10 feet high and 4 to 12 feet wide depending on species and cultivars. Natural shrub form is arching. Many forsythias outgrow their space within a few years.

They are frequently planted too close to building and home foundations. What results is clipped boxy hedges or round balls with few flowers. Fall pruning also removes a majority of the pre-formed spring flower buds, which is the main reason you grow forsythia.

Forsythias bloom best in full or partially sunny location. They’re not fussy, growing in any average soi,l and are insensitive to acidic or alkaline pH soils. They have few pest problems although deer browsing in some areas. Spread a slow-release shrub fertilizer in spring if growth is slow or if flowering is sparse.

Prune immediately after flowering has finished in spring. Cut out one-third of the stems to the ground each year to retain its natural arching form plus tip prune to reduce overall size.

Forsythias make excellent specimen shrubs; group several 6-8 feet apart to create a hedge; plant on steep bank for erosion management.

For small sized forsythias, try Gold Tide ® (Courtasol’) that grows 1 – 2 feet tall and 2-4 feet wide. ‘Little Renee’ grows 2 feet tall and 4 feet wide. Goldilocks® (‘Courtacour’) @ 2-3 feet tall and wide; ‘Show Off’ @ 5 feet tall and 6 feet wide; ‘Fiesta’ @ 5 to 6 feet tall and wide and variegated leaves.