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

Calamint – 2021 Perennial Plant of The Year (PPOY)

Posted by Hugh on January 1st, 2021

Too begin a new gardening year, the Perennial Plant Association has named calamint (Calamintha nepeta ssp. nepeta) as the 2021 Perennial Plant of the Year. One landscaper designer describes calamint as “a cloud of confetti, tiny white flowers”. Plants are dotted with masses of tiny white (or pale blue) flowers from early summer to fall.

White flowers of calamint in summer garden (Photo credit: Midwest Groundcovers)

Calamint is a member of the mint family and a close cousin of catmint (Nepeta faassenii), another PPOY award winner. Flowers in turn attract loads of small butterflies. Undemanding, this low-maintenance deciduous perennial is native from Great Britain to Southern Europe. It grows best with good soil and air drainage (USDA hardiness zones 5-7).

Calamint grows 15-18 inches tall and wide in full sun and in average garden soil. It exhibits a low mounding or bushy habit, ideal for the front of the border, rock gardens, and more.

It exhibits above average drought tolerance once established. You may shear back lightly if desired to create neater habit or refresh spent blooming stems. Once a 1-year establishment period, calamint exhibits good drought tolerance.

Calamint (photo courtesy of Midwest Groundcovers)

Calamint stays disease and pest free. It blooms throughout the summer and its aromatic foliage is deer-resistant. It is an ideal companion planted with other late summer blooming perennials as fall anemones (Anemone), asters (Symphorocarpus), obedient plants (Physostegia), turtleheads (Chelone), garden phlox (Phlox paniculata), and ornamental grasses such as ‘Northwind’ switchgrass (Panicum), Little bluestem (Schyzacharium), and muhly grass (Muhlenbergia).

Caring For Thanksgiving/Christmas Cacti

Posted by Hugh on December 26th, 2020

Holiday cacti are not true cactus plants. They are native to tropical rainforests of South America and their care is much different than desert cacti. Christmas and Thanksgiving cacti refers to the time that they bloom in Fall.

Thanksgiving cactus (Schlumbergera truncata) and Christmas cactus (S. bridgesii are available in several flower colors: red, salmon, pink, purple, orange and cream. Most plant hobbiests grow them in hanging baskets, their stem branches gracefully arch over the edges of pots.

Holiday cacti do not have true leaves. The flattened green stem segments (called “cladophylls”) identify the kind of cacti that you are growing and exhibit soft teeth and no spines. Thanksgiving cactus has the most prominent teeth or claws along the edges and also bloom earliest – around the Thanksgiving holiday. Christmas cactus segments have rounded segments.

Holiday cacti thrive in a well-drained, organic-rich, moist
soil (media) and are placed near a well-lighted window in your home or apartment. Grow them in clay or plastic pots with bottom drainage hole(s) to allow excess water to drain off into a saucer or a shallow tray of gravel. BUT, do not overwater these plants. Their arching segmented stems make them ideal hanging basket plants.

During the active spring and summer growing season, keep the media evenly moist. Over the summer, set the pot outdoors under a shade tree or on a partially shaded deck or patio. In early fall, flower buds will form in response to short day photoperiod and cool outdoor temperatures. Below 45 °F, bring plant(s) indoors and increase watering intervals by 2-3 days longer.

New growth start out from the branch tips in late winter or early spring. Holiday cacti are low constant feeders when actively growing. Fertilize through summer months with any house plant fertilizer twice monthly or a water soluble fertilizer such as Miracle-Gro™ or Peters™ @ one teaspoon per gallon of water. Feed the non-blooming plant once every 4-5 weeks over the winter months.

Holiday cacti do not require annual repotting and will grow potbound for 3-4 years. Prune to reshape the plant during the winter rest period in February. Snip off unsightly foliage at any time of year. Inspect plants periodically for mealy bugs and scale. If bugs are present, spray with neem oil or insecticidal soap, sold at independent garden centers and garden shops.

Anthuriums Thrive in Low Light

Posted by Hugh on December 16th, 2020

Anthurium pots in Biltmore Estates Conservatory, Asheville, NC

Anthuriums are easy to grow houseplants. They have become wonderful plant gifts around the holidays and birthdays. First and foremost, anthuriums are low light tropical plants. They grow best in bright, indirect light, but produce fewer flowers in low light.

Anthuriums sport long-lasting glossy, deep-green leaves and sturdy flowering bract-like blooms. The flowers of an anthurium is actually a
spiky spadix that grow out of the plant stem surrounded by a spathe or modified leaf. Spathe colors vary from red, pink, coral and white. In warm southern areas (USDA zones 10 or higher), plants can be grown outdoors in shady outdoor areas where their bright, heart-shaped blooms stand out.

Do not place anthuriums in direct sunlight as the leaves will sunburn, lose their color or suffer from leaf edge scorch. Anthurium care also demands that the soil drains freely but retains some water. Plants prefer warm temperatures between 70 – 90° F and will stop growing when room temps drop into the low fifties. Room humidity is best above 50%, best achieved by daily spritzing plants or setting pots on wet gravel. As a houseplant, grow in a potting soil designated for tropical plants. In the deep South, plant in a well-drained garden spot or container.

Anthuriums are susceptible to root rot… so too much water can cause the roots to die. Plants do not require much fertilizer. Feed with a weak one-quarter (1/4) strength fertilizer solution once every 3 to 4 months. Feed with water soluble products like Miracle-Gro™ or Peters™ that contain a high amount of phosphorus (P).

Their thick leaves are generally not troubled by insects that chew leaves. Occasionally, sucking insects like aphids, mealy bugs, and mites may feed on plant sap. Catch infestations early and spray a Pyrethrin-based insecticide, a horticultural soap, or oil spray.

Anthuriums need to be repotted every 2-3 years or earlier if water quickly pours through and out the drainage hole. Potbound plants have roots circling around the surface of the potting soil or some roots growing through the drainage holes.

Warning: Anthuriums are poisonous if ingested and the sap may also cause skin irritation.

Repel Deer And Rabbits

Posted by Hugh on December 11th, 2020

We live at a time that deer population numbers have grown out of control in many areas of the U.S. The internet lists plants that “DEER DON’T EAT”. However, deer have not read these lists, and secondly, a starving deer will eat just about anything. An adult deer may eat 5-6 pounds of plant material each day. Hungry deer can stripped a landscape clean, particularly it contains a plant smorgasbord that they love such as
your fabulous collection of hostas.

In some states ridding deer from a suburban landscape may also be a health concern. Deer harbor ticks that can carry Lyme disease and Rocky Mountain spotted fever.

Deer can be effectively managed by mechanical means. This typically involves fencing around your property or an entire subdivision. The fence must be tall enough to keep leaping deer out—at least 7 feet high. Fencing is a very expensive and several secondary alternatives are listed below.

Education signage at Longwood Gardens, Kennett Square, PA

Many property owners spray deer repellents on valuable plants. No repellent is foolproof but several have proven to be effective short term remedies to reduce deer feeding if used regularly and correctly timed.

Basically, there are two ways to keep deer away from your landscape: 1. Deterrents (odor) and mechanical types:

Odor Deterrents their effectiveness varies largely on how quickly the deer adjust to them. Some may work only a few weeks. Examples of deterrents: human hair, decaying fishheads, blood meal, garlic, hot pepper, fabric softener, processed sewage, motel bar soap, and many others.

Deer Retardants And Repellents that keep deer away: many formulations are available at garden centers and hardware stores nationwide.

Plants With Thorny Branches Repel Rabbits and Deer such as hawthorns (Crataegus), barberries (Berberis spp.), Trifoliate orange (Poncirus trifoliata), and roses (Rosa spp.).

Annual Flowers with aromatic fragrances repel rabbits such as Sagebrush or wormwood (Artemisia), Snapdragon (Antirrhinum), Zinnia (Zinnia), Cardinal flower (Lobelia), Wax Begonia (B. semperflorens), zonal geranium (Pelargonium), Vinca (Catharanthus), Ageratum, Calendula (pot marigold), sunflowers (Helianthus).

Mechanical Deterrents – examples include:
Floodlights
Noise-makers – radios, fireworks, whistles, and others
Reflective objects such as aluminum pie tins, party streamers
Electric wires, fishing line, sprinklers
Fences – including Electrified fences
Grates and Moats

Hungry deer will eat almost anything, even those plants listed on the “won’t eat” list you may find on the internet. Eliminate favorite areas, like small fruit and vegetable gardens or home orchards. Deer in different parts of the country also have different food palates.

Three Common Witchhazel Varieties

Posted by Hugh on December 6th, 2020

Common witchhazel (Hamamelis virginiana) is likely the last native woody shrub or tree to bloom in the northern areas of the U.S. and Canada (USDA hardiness zone 3-8). This autumn blooming deciduous shrub or tree grows in open woodlands, often near a lake or a stream bank. Common witchhazels grow 15-20 feet tall as a large shrub and 25 feet as tree form. Three cultivars are available, and are mostly sold by native plant specialty nurseries in your state or region and on-line.

Clusters of yellow ribbon-like flowers appear along multiple branches from October to December during or after leaf drop. Blooms are fragrant upclose. Medium to dark green circular (ovate-obovate) leaves turn yellow in fall. Rating of the fall leaf color varies from one year to the next. Green seed capsules form the following spring and mature to light brown in late summer.

No serious insects or diseases affect witchhazels. Insect leaf galls, caused by small wasps, may appear infrequently on foliage. Japanese beetles may chew on summer foliage causing minimal damage.

Cultivars: ‘Little Suzie’ (semi-dwarf, 4 to 5 ft. shrub); ‘Green Thumb’ (15 feet; yellow/green variegated leaves; soft yellow flowers; ‘Harvest Moon’ (18 feet high; late blooming lemon yellow (which happens after leaf fall).

Set balled and burlapped (b&b) or container-grown nursery stock in any season of the year. Witchhazels grow best in partial to full sun (minimum 6 hours sunlight) for high flower numbers.

Soil: grows in any soil that is mildly acidic; tolerates wet soggy ground.

Watering: exceptionally drought tolerant after its first year.

When to prune: prune into multi-stemmed small tree or naturally as a shrub to a desired height and width in late winter or early spring.

In the landscape: Common witchhazels are nature’s last hurrah; long-lived fall blooming native shrub or small tree; three new better cultivars improves its landscape versatility; attract wildlife; bring cut boughs indoors for decoration and floral fragrance.

Is Your Home Ready For Monstera?

Posted by Hugh on December 1st, 2020

Monstera, aka Swiss Cheese Philodendron or Split-leaf philodendron (Monstera deliciosa) is a climbing evergreen member of the Arum family (Araceae) native to the tropics of Central America. It may also be grown outdoors in (USDA plant hardiness zones 10-12).

Monstera is grown for its large cutleaf foliage, sometimes perforated, that may grow up to 3 feet long. Some forms with perforated foliage earns it the name “Swiss cheese plant”. It survives in the warm 70°F dry air and low light environs of modern homes and is also a popular office and house plant. Monstera is a tropical vine, but can survive resting temps between 50 to 60 °F over the winter months.

Young gardeners, particularly millennials (born between 1981 to 1996) appear to be highly captivated about this huge house plant. Water pots every 7-10 days and more often if the plant is seriously potbound. Plants are usually grown in large pots and should be occasionally showered down in the tub to provide humidity and to rinse dust off the foliage. Set a leak-proof plastic mat under the plant so as not to damage room flooring and/or carpets.

Fertilize your plant once monthly from late winter (March) to fall (October) with any product labelled for house plants. Reduce watering and do not feed during the winter (November thru February). Remove dust with a damp sponge or paper towel.

Split Leaf Philodendron at a garden center

Water regularly and allow the soil to dry out slightly between waterings. Reduce watering in fall and winter. Mist the leaves periodically to increase room humidity, particularly during the winter months in northern U.S. homes.

If you live in the deep South or in southern California (zones 10-12), outdoor plants may flower and produce edible fruits with a taste similar to pineapple. In warmer climes, monsteras will grow up attached to a yard tree, trellis or a pole made from bark.

Inspect foliage for common pests such as mealybugs, aphids, thrips, scale and spider mites. Most pests can be removed by directing a coarse spray of water to the leaves. Insecticidal soap will also help eliminate troublesome pests.

Warning: Some parts of the plant, particularly the leaves, can cause intense mouth burning, nausea, vomiting, diarrhea, and minor skin irritation.

Houseplants Improve Your Home Atmosphere

Posted by Hugh on November 26th, 2020

Houseplants decorate as well as clean the air at work and in homes or apartments, particularly when windows are closed over the winter months. Doctors tell us that an environment filled with lots of plants help to lower blood pressure, reduce stress, and improve mind function, particularly our ability to concentrate.

Here are six easy care foliage plants that filter indoor air:

1. Ferns – non-hardy ferns, not the ones we plant outdoors, come in a wide variety of sizes, shapes, and shades of green. Textural and elegant, many ferns look good in almost any home decor. Two of the best are long-lived Asparagus fern* (Asparagus sprengeri) and birds nest fern (Asplenium nidus), the latter with attractive long spear-like glossy fronds. Keep room humidity high around ferns by daily misting and setting them on a pebble tray.

2. Dracaena – reliable carefree houseplants that tolerate low light, low humidity, and infrequent watering. Dracaenas come in all sizes, from 3-inch pot plants to towering specimens. Many offices select dracaena varieties as foliage plants, such as corn plant (D. fragrans) with wide, long leaves that arc gracefully from the stalk, and dragon tree (D. marginata) that can grow to the ceiling. Dracaenas ares the perfect addition to desks and tabletops.

3. Chinese Evergreen (Aglaonema) – decorative striped leaves and occasional flowers make these attractive plants favorites in most homes. Plants can be neglected for long periods and still be happy.

4. Bromeliads, members of the pineapple family, are stylish easy care plants that adapt to modern home environments. Bromeliads produce colorful, long-lasting blooms and sword-like green leaves. There are so many to choose from and their colorful flowers come in shades of red, pink, orange and yellow.

5. ZZ Plant (Zamioculcas zamiifolia) – easy to grow and care for indoor plant that displays small glossy leaves on stems which can grow up to 3 feet high. It grows well in either low or bright lighting and with frequent or much less frequent amounts of water.

6. Snake plants (Sanservieria), also called “Mother-in Law” tongue are houseplants that you can’t kill (or you’ve got to try harder). There are several kinds available. Shop at your local independent garden center that has a good selection.

* not a true fern, a member of lily family (Liliaceace)

Growing Cyclamen In The Home

Posted by Hugh on November 22nd, 2020

Cyclamens, the non-hardy forms, have become popular gift plants. Cyclamens are incorrectly labelled as tropical houseplants at garden shops. Many people enjoy this flowering plant for long as possible and toss it once blooming has stopped.

Cyclamens enjoy a long blooming period indoors in a cool room and are fussy, a bit of a challenge when you try to rebloom them. In the home cyclamens prefer a bright, indirect sunlight and cool surroundings between 55 – 65 °F. If the thermostat is set at 70 °F or higher, stems start to stretch and flower production declines and ceases. Cyclamens also demand high room humidity. This is best accomplished by sitting the plant on a tray of moist pebbles nearby other plants, or to add a room humidifier. Don’t mist the foliage!

In the spring cyclamens often go dormant. Allow the soil to dry out and clip off all yellowed and dry leaves. Give the plant a rest in a cool dry spot through midsummer. New growth should start to emerge sometime by early fall. Around this time repot into a slightly larger pot containing fresh compost-rich potting soil, begin watering and feeding again.

Repot into a slightly larger pot containing fresh compost-rich potting soil and grow it in the same bright, cool location. Feed cyclamens every two weeks with a weak ¼ solution of a water soluble fertilizers like Peters™ or Miracle-Gro™ or with Schultz’s Houseplant Food™.

Lastly, in the deep South (Florida, along the gulf coast, Texas, and Southern California), cyclamen adorn outdoor planters during mild fall, winter, and early spring when temperatures are in the 40’s and 50’s at night. Non-hardy cyclamens do not tolerate frigid temperatures below 40 °F (4 °C).

Coast Leucothoe a Better Choice

Posted by Hugh on November 16th, 2020

Compared to other doghobble species, coast leucothoe or doghobble (Leucothoe axillaris) is a best choice for Southern U.S. landscapes (USDA zones 6 -9). This species is native to open woodland areas of the Southeastern U.S. The species grows along woodland slopes usually nearby a water source. However, its roots do not tolerate perennially damp ground.

Doghobbles are low-growing evergreen shrubs or ground covers. They exhibit a low, wide spreading form and oval, leathery, toothed dark green leaves. They grow 2-4 feet tall and 3-6 feet wide and are possible substitutes for boxwoods in moderately shady areas. In mid-spring shrubs are covered with showy clusters of urn-shaped white to pink flushed flowers.

One to two hours of direct morning sun is beneficial in northerly areas (zone 6 – 7a). In southerly climes (zones 7b-9), foliage may burn in the winter sun under deciduous shade. The arching dark green glossy foliage often turns bronze in cold habitats. Shrubs withstand heat and humidity. Doghobbles grow in a humus-rich, acidic, well-drained soil.

Flowers form along axillary branches as droopy spikes of white waxy bell flowers that are lightly fragrant. Branches grow zig-zagged at the tips and the lance-shaped, dark-green, glossy foliage turns red-green and purple in winter.

In highly humid regions of the U.S., 1-2 hours of direct early morning sunlight discourages leaf spotting. Doghobbles do not tolerate droughty soils or drying winds. Every 5-6 years, rejuvenate shrubs by cutting them to the ground after flowering.

After spring bloom, feed with any acid based fertilizer recommended to azaleas and rhododendrons. Mulch with acidifying coverings like pine needles and pine chips to keep roots cool and weed-free. Doghobble is highly deer resistant.

Wide plant spacings and good air circulation are keys to avoiding leaf spotting issues. Anthracnose leaf spot, tar spot, powdery mildew, leaf gall, lace bugs, and scale insects are occasional problems. Coast leucothoes tend to be less leafspot susceptible.

Persimmon – Native Fruit Tree

Posted by Hugh on November 11th, 2020

Persimmon (Diospyros virginiana) is a deciduous U.S. native that grows 35 to 60 feet tall and 25-35 feet wide (USDA hardiness zones 4 to 9). Mature trees have a rounded oval crown. Ovate to elliptic, 2-6 inch long leaves, alternative along the stem, are glossy dark green above. Autumn leaves turn yellowish-green, infrequently reddish purple.

Persimmons grow in a wide geographic range from southern New England to the Midwest and south to Florida and Texas. Trees are usually dioecious (separate male and female trees), although some trees have perfect flowers. Tree roots tend to sucker prolifically and form almost impenetrable thickets. Its distinctive thick, dark gray bark is broken into rectangular blocks.

Persimmons are not fussy regarding site selection. Trees grow in average, dry to medium, well-drained soils, and in full sun to partial shade. Established trees are drought tolerant. Removing suckers by mowing around a tree(s) is the easiest practice. Female trees need a male pollinator in order to set fruit.

Fragrant, white to greenish-yellow flowers which are difficult to spot, bloom in late spring, with the male flowers appearing in clusters and the female flowers appearing solitary. Edible persimmon fruits, about 1-2 inches across, mature in fall, usually following the first hard frost to an orange to reddish-purple color, and may persist on the tree into winter.

Persimmon fruit is quite astringent when green, but upon ripening becomes sweet and may be eaten off the tree. The large seeds are surrounded by sweet orange flesh, which is edible and tasty eaten fresh or used in syrups, jellies, ice creams or pies. Persimmon leaves can be used to make or flavor teas.

Persimmon fruits are globose, with orange-gray, bitter skin and four large sepals at the top. The fruits are eaten by many wild animals, but can be poisonous to horses if eaten in excess. The wood of this hardwood tree is used to make golf club heads, billiard cues and shoe lasts.