Native Sundrops to Stabilize a Slope

My garden has a steep incline leading away from the house. We had switchback paths graded into the slope so that we are able to zig-zag down to the creek without mountain-climbing gear. The slope is semi-terraced by the paths. Rainfall plays havoc with the area, washing away the chips on the footpath and occasionally moving the heavy tree trunks positioned to stabilize the edges of the paths. Our deer, foxes, and bears use these flat walkways to travel across the area.

I have established a number of showy shrubs, bulbs, small trees, and perennials along the switchbacks. In my imagination, I see this as evolving into a specimen walk. Right now, I’m concentrating on huffing and puffing up the slope more than the progress of the plants. Because I am a thrifty gardener, my plantings are all tiny when first installed. I am confident that they will either thrive… or die. I allow new plants three years to settle in and demonstate success. I may choose to relocate a few disappointments to different sunlight exposure, but there are too many good plants available to tolerate poor performers. Over the past four years, I have lost a few: Illicium floridanum ‘Florida Sunshine,’ (planted in too much blistering sun), yellow ‘Sunshine’ Ligustrum sinense (not enough water), and ‘Emerald Green’ Arborvitae (all their bark and most branches removed by deer). 

I am trying to be smarter with my plant purchases these days by drafting a “musts” list and a “prefer” list before I hit the garden centers. For this area, plants must prefer full sun, and be deer resistant, drought tolerant, and low maintenance. I would prefer native, spreading but not invasive, long-flowering plants that are attractive to pollinators.

I just purchased and planted six Sundrops, also known as Narrow Leaf Evening Primrose. Native Oenothera fruticosa, pronounced ee·nuh·THEE·ruh has bright yellow flowers that are open only during daytime. It spreads but is not invasive, unlike the pink flowering Oenothera speciosa (UGH!) that I waged war against for years before I could eradicate it.

Sundrops are a drought-tolerant pollinator plant that is reputed to be deer-resistant. The slightly cupped flowers of Sundrops provide nectar for hummingbirds, and birds eat the seeds. They will grow in most soil types and most pH ranges, full sun, in zones 4-8. References say that they bloom from April through August, which is longer than many perennials. They flourish in heat and are used to stabilize soil on slopes. They can play a prominent role in rock gardens, native gardens, cottage gardens, and meadows. I’m looking forward to seeing how long-flowering they are in an area with zero irrigation.

A hedge of Sundrops. Photo by Leonora (Ellie) Enking CC-BY-SA 2.0

Helianthus for Sunny Yellow Fall Flowers

While every other perennial plant is winding down at the end of the summer gardening season, the golden heads of Helianthus are approaching peak show. You will notice that I included the genus but not the species. That is because I cannot tell one species from another. What I can tell you is that I spotted this lovely fall-flowering yellow daisy last autumn in a ditch in front of a house with prominently displayed No Trespassing signs. I jumped from the car, snipped one stem of spent flowers, and zoomed down the street before the owners could lock and load.

I stripped the seeds from those dried flowers and started growing them in my laundry room. (This was before the greenhouse arrived.) I had a couple of small plants to set out in spring. They have repaid my care by throwing a dozen lovely yellow flowers per plant. These are hardy perennials for zones 6-9, so I expect the show to improve next year and every year thereafter.

Helianthus, commonly called Swamp Sunflower or Narrow-Leaf Sunflower, is a native that attracts songbirds and butterflies. It has rough, narrow leaves and thin stems that can be damaged by winds or weighted down by its numerous flowers. It is a food source for several butterfly larvae species. Plants are moderately deer resistant.

Perennial species of Helianthus, pronounced hee-lee-AN-thus, share common cultural needs. They flower best in full sun but will tolerate partial sun. They want acidic soil. Plants will get quite tall – to ten feet in fertile soil and sufficient moisture. That is too tall to fit into most garden borders. This too-tall problem can be remedied by pinching plants back several times in spring and early summer to encourage branching and reduce their height. Don’t pinch after mid-summer to avoid removing flower buds.

Allow spent flowers to remain on stems to reseed naturally and your fall garden will soon feature these happy yellow flowers, perfect for inclusion in seasonal flower arrangements.

These are two of the seedlings I started from seed. I will not deadhead them. Instead, I will allow the fallen seeds to start new plants, resulting in a fuller planting in coming years. The bumblebees LOVE these flowers.

Blanket Flowers for Color in the Heat

Gaillardia x grandiflora is a hybrid between G. aristata and G. pulchella). Commonly known as Blanket Flower, hybrid Gaillardia (pronounced gay-LAR-dee-uh) is a short-lived perennial in zones 7-10. Plant heights range from one to three feet tall with a two-foot spread. It has hairy leaves and produces bright, daisy-like flowers that bloom in a wide variety of colors, including red, orange, yellow, and purple. The flowers are typically 2-3 inches in diameter and have a central disk surrounded by bright single color or bicolor petals. Plants often produce flowers from spring to fall, especially if deadheaded. Leave a few dead heads in place as a treat for goldfinches, who love the seeds. Plants may reseed themselves. Cut flowers last a long time in the vase. Flower centers remain attractive after petals fall, and can be used fresh or dried in flower arrangements.

Plant Gaillardia in full sun only, in neutral soil. Plants dislike poor drainage and will decline in heavy or too wet soils. They are drought tolerant once established, and are a good choice for a xeric garden or pollinator garden. They are rarely browsed by deer or rabbits.

I went to the nursery last week with no intention of purchasing Gaillardia ‘Spintop Red’ but somehow these ended up in my list of purchases. What kind of doofus plants perennials in the midst of a heatwave? THIS kind, apparently. I love the prickly seedheads, right, as much as the flowers.

Bee Balm is Nature's Form of Fireworks

Fireworks exploded across the nation Monday night in celebration of Independence Day. In the garden, Bee Balm (Monarda didyma and Monarda fistulosa) blooms are exploding into Nature’s version of fireworks. Monarda is pronounced moe-NAR-da.

Bee Balm is a heat-loving, native perennial that should be in every sunny pollinator garden. Its square stems tell the gardener that it is a member of the mint family. Like mint, it spreads aggressively by underground runners and can become invasive if not restrained. Plants are hardy zones 4 through 9. They prefer acid to neutral soil, and tolerate heavy clay. They are heat-tolerant, but moist soil produces a prettier, healthier specimen.

Bee Balm can be propagated by seed, division, or cuttings. To prevent spreading, create a collar by cutting the top 4-5 inches off a nursery pot, then sinking it a couple of inches into the soil around the plant. The collar will serve as a STOP sign to encroaching roots. Be alert for any small plants that manage to evade the barrier. After a couple of years, lift congested plants, divide, and replant.

Plants can reach four feet or more, and may need staking to keep them upright after summer thunderstorms. They tend to flop when grown in part-sun areas. Older cultivars developed a bad reputation for their proclivity to disfiguring mildew and rust. New introductions are both disease resistant and shorter to reduce the need for staking. ‘Jacob Cline’ (red) and ‘Grand Marshall’ (fuchsia to purple) are two mildew-resistant cultivars. Good air circulation helps prevent mildew problems. If your plants fall victim to mildew, try to ignore the ugly leaves rather than using fungicides that may have a negative impact on pollinators.

Bee Balm blooms have a complicated structure which is better demonstrated by a photo than description. Plants have an extended flowering period even if they are not deadheaded, although removing spent flowers make a more attractive show.

Bees, butterflies, and hummingbirds love the flowers, while deer and rabbits leave plants alone. This may be because of the strong fragrance of the foliage. Bee Balm is one of the rare plants that will grow well near Black Walnut trees. The leaves and flowers can be used to make teas or flavor jellies. Presumably, the Oswego Indian tribe brewed the leaves, because a common name that has fallen from wide use is Oswego Tea.

This Bee Balm appears to advantage when seen against a fence.

The equivalent of an “Eat Here” sign for pollinators.

This sign made me giggle. The nursery hired someone who wasn’t familiar with Bee Balm, so the new employee labeled it as he heard it: B Bomb. (I blurred the name of the nursery out of respect.)

Catnip As A Mosquito Repellant

Does catnip  (Nepeta cataria, pronounced NEP-eh-tuh kat-AR-ee-ah) repel mosquitos? A recent article in iScience says, “Yes.” (Read the full text here.)

A perenial herb, catnip is among a group of plants that produce compounds, called iridoids, which discourage insect attacks. Two of these compounds are nepetalactol and nepetalactone. The latter substance attracts cats, who often nibble the leaves or rub against the plants. A couple of our felines prefer to dive into the middle of mine as if they are wading pools on a steamy day. Then they aimlessly race around (“the zoomies”) for a while before they collapse for a nap. If disturbed, they may open their dilated eyes and acknowledge my presence with a little chirp, almost as if saying, “That’s some good Nip, man.”

Now, science tells us that those same compounds are an effective mosquito repellant. A research collaboration between Northwestern University and Lund University (published in Current Biology journal) indicate that crushed catnip can be as effective as the synthetic compound DEET and is safer. Silver vine (Actinidia polygama), a relative of the Kiwi vine, has even more insect-fighting substances although it is less commonly grown.

Simply growing catnip near your deck, pool, or treehouse will not do the deed. Leaves must be damaged (torn or bruised) to release the mosquito-fighting magic. The oil from crushed catnip leaves also repels fruit flies.

Catnip is easily started from seed or can be divided. It will grow in full sun to part sun in any well-drained soil, zones 3 through 9, preferring part sun in hotter zones. It has attractive spikes of blue-to-purple flowers that bees and butterflies love. As a member of the mint family, square-stemmed catnip is a vigorous grower and can become woody and shrub-like with age. Prune it back hard after blooming to encourage repeat flowering and keep the plant compact. The next time I prune those in the Mary Snoddy garden, I plan to put squashed leaves and stems around the deck to test out the mosquito-repelling scheme.

Nom, nom, nom.

Amsonia - A Two-Season Star

Amsonia hubrichtii, (pronounced am-SO-nee-yuh hew-BRIK-tee-eye) is flowering right now. This Arkansas native’s soft blue flowers are held at the top of tall stems that waft gracefully on the breeze. Leaves are narrow, leading to the common name Threadleaf Blue Star. Its fine, feather-like texture contrasts well with broad-leaf perennials like Black-Eyes Susans or Coneflowers. It also looks pretty when planted next to burgundy foliage plants like Ninebark, Smokebush, or Loropetalum.

While the spring flowers are pretty, Amsonia’s best season is fall. Those narrow leaves turn a golden yellow that glows in sunlight. For maximum impact, pick a site where the late afternoon sun provides a backlight.

Amsonia is undemanding. Give it full sun or mostly sun and it will be happy in zones 5-8 . Too much shade or excess water will cause it to flop. In rich soil, it may grow so tall that it opens up in the center in late summer. It takes at least a year or two for Amsonia to reach its potential. Don’t pull it up prematurely. Mature plants will reach heights of three feet, with a equal spread. Prevent the flopping or center separation by pruning it back to a height of six inches immediately after flowering ends. Cut to ground level just before spring growth commences.

Amsonia hubrichtii was the Perennial Plant Association’s “Plant of the Year” in 2011. Amsonias look great planted in masses. Flowers attract butterflies, and deer don’t seem too interested.

The blue flowers of Amsonia float at the top of thread-like foliage.

This Amsonia is just beginning to show hints of fall. In a few weeks, it will be a mass of butter-yellow leaves.

Lavender Scent for Stress Relief

Politics and pandemics. Hurricanes, wildfires and home schooling. Many of us are feeling stressed. In times of increased tensions, it is tempting to turn to food or drugs to regain our equilibrium (read: to avoid lashing out at the ones we love). The scent of lavender is a natural time-tested anxiety reliever.

Folk medicine has long proclaimed lavender as an effective stress reducer. (Fans of the Downton Abbey series may remember Anna stuffing a sleep-inducing pillow with dried lavender blooms, circa 1920s.) Now the scientific community agrees. A study released in 2018 indicates that linalool, the magic substance in lavender, must be inhaled rather than injected directly into the bloodstream to be effective. In this instance, the marketing world has a head start. There are laundry detergents, candles, deodorants, lotions, air fresheners and even a pillow spray containing this calming aroma. The good news is that home gardeners can grow their own.

Lavender is a member of the mint family. The most common types are English lavender (Lavendula angustifolia) and Spanish or French lavender (Lavendula stoechas or Lavendula dentata). English lavender is the hardiest type, being cold hardy into Zone 5. ‘Hidcote,’ ‘Superblue,’ and ‘Munstead’ fall into the English family while ‘Bandera’ and ‘Primavera’ are Spanish rebloomers. Modern crosses between the two types produce heavy blooming, cold hardy types like ‘Torch,’ ‘Provence’ and ‘Edelweiss.’ All these have flowers in the blue to violet range, but pink and white cultivars are available.

Lavenders are challenging to raise from seed, with low germination rates and slow growth. Start with a purchased plant and propagate from cuttings or layering. Growing Lavenders in clay soil and high humidity of the southeast can be challenging. Like other plants with felted gray leaves, they are heat tolerant but prone to rot if the leaves stay damp. They must be sited in full sun. Water only until plants are established; avoid wetting foliage. They are quite drought tolerant thereafter. Because plants need good drainage and good air circulation, they are ideally suited to rock gardens or container culture. Bagged potting soils labeled for cactus work well. Plants prefer a lean, alkaline soil, so do not add fertilizer but do add lime to keep a pH of 6.4 to 8.2.

Plants may eventually reach heights of 4 feet or more. Tall plants tend to flop open in the middle. This can be prevented by selecting dwarf cultivars or pruning (remove up to 1/3 of the foliage) immediately after they bloom – a perfect opportunity to harvest the flowers for potpourri or even food use. I enjoyed a delicious lavender shortbread cookie several years ago at a gardening event. Lavenders bloom on new growth, so pruning keeps them compact and increases the number of flowers. If pruning is neglected, plants will eventually develop leafless woody stems at lower levels. Once this occurs, replace the plant with a new one. Plants rarely throw new growth when pruned down to this woody section.

Lavenders are evergreen to semi-evergreen. Both flowers and foliage are fragrant. They are not browsed by deer, are not aggressive and are not invasive. Blooms are long-lasting. Bees and butterflies love them.

Lavender is the National Garden Bureau’s Perennial of the Year for 2020. They have kindly provided the accompanying photographs.

Anouk Bandera Purple

Big Time Blue

Hidcote Blue

Munstead

Primavera

Portion