sustainable gardening – Page 5 – Extension Master Gardener Volunteers of Durham County

By Melinda Heigel, NC State Extension Master Gardener^SM volunteer of Durham County

This is the second installment in an ongoing series called Plant Detective, where we uncover science-based information on strange and mysterious sightings in the plant world.

Details of the flower and stem of the mystery plant I recently discovered on a walk with dogs Baby and Cole, assistant plant detectives. While it looked like a cross between a bee balm and lamb’s ear, it was something I’d never seen before! (Image credit: Stan Shebs CC BY-SA 3.0; Linda De Volder CC BY-NC-ND 2.0)

On one of our daily dog walks, I recently stumbled across a plant I simply could not identify. It was a gorgeous mounded shrub with fuzzy, soft, gray-green leaves–the kind you just have to touch–and a lot like the lamb’s ear (Stachys byzantina) or the garden sage we all know. Graceful arching stems sported multiple flower clusters along each stem, much like snapdragons (Antirrhinum majus). And the vivid yellow flowers encircling the stem looked like a silly court jester’s hat. In a more appropriate botanical reference, they appeared similar to the bee balm flower (Mondara spp.). What was this cool plant? An online search of the NC Extension Gardener Plant Toolbox turned up a positive ID: Jerusalem sage (Phlomis fruticosa).

Characteristics and Growing Conditions for Jerusalem Sage

(Left to right) The large stand of Jerusalem sage I encountered was nearly 5 feet tall and 5 feet wide and acted as a small hedge for the homeowner’s landscape. Once the flowers drop, textural seed heads continue to provide visual interest. Deadheading the plant can encourage longer bloom time. Seed heads eventually turn brown and can be a food source for birds in the fall. (Image credit: Melinda Heigel)

A member of the mint family (Lamiaceae), Jerusalem sage is native to arid yet temperate Mediterranean regions like Greece, Italy, Cyprus, and Albania. It is also naturalized in southwest England and parts of California. This plant has a mounding habit and can function like a shrub or subshrub. Depending on the variety, it can grow up to 4 feet wide and 5 feet tall. Silvery-green velvety leaves are around 5 inches long and have a pleasant scent. Tall vertical stems rise from the plant and support whorled flowers repeating along its arches. And while the 2-to-3-inch flowers have no scent, they are spiky and eye-catching. The plant I stumbled across had a brilliant yellow flower. Other species of Phlomis have a soft pink bloom.¹

You can see why the plant’s common name includes the word “sage.” Its soft velvety leaves resemble that of our edible herb garden sage (Salvia officinalis) and other ornamental Salvia plants, even though they are not related. (Image credit: Melinda Heigel)

While these plants have the reputation of being fairly adaptable in many soils, well-drained soils are are a must. This perennial prefers full sun and can perform in part sun; planting it in shade will often result in a leggy plant short on its spectacular spring and summer blooms. In our region of central NC (Zone 8), Jerusalem sage is evergreen; in Zones 5-7, it’s deciduous.

Jerusalem sage has a long list of positive attributes. Overall, this plant is low maintenance and resilient. While weeks of drought like we’ve recently experienced might call for some supplemental watering, it needs little extra irrigation once established. It is heat tolerant and prefers leaner soil (read no fertilizing). It grows quickly but generally is a well-behaved inhabitant in the garden, only requiring you to prune to maintain shape and lightly in late winter before spring growth commences. If you are willing to do the work, deadheading spent flowers in the spring means you will enjoy additional flowering, thus extending the bloom cycle throughout the summer.

With only leafhooper insects as a potential threat, Jerusalem sage has no serious pests or pathogens. Here’s a big bonus–this plant is both deer and rabbit resistant, and its flowers are attractive to bees, butterflies, and hummingbirds. Spent seed heads can also provide food for songbirds.

How to Use Jerusalem Sage in the Landscape

This plant can wear many hats in the garden. It’s suitable for containers or as a stunning specimen plant. Planted en masse, it could make a great year round statement. As in the landscape where I first saw it, it can serve as part of a mixed screen planting bordering a yard. Given its height, it’s probably best as a “back of the border” plant in a mixed bed.

In terms of garden design, I can see this versatile plant looking right at home in a cottage-style garden of glorious native perennials like purple coneflower (Echinacea purpurea), sunflowers (Helianthus spp.), butterfly milkweed (Asclepias tuberosa), and scaly blazing-star (Liatrus spicata). Equally, I can see it as a stunner alongside other water-wise plants in a xeriscape of agave, yucca, and cacti like our native eastern prickly pear (Opuntia humifusa).

I hope you’ve discovered a new plant right alongside me this week. Given the challenging environmental changes we continue to see, I am planning on giving this easy-to-grow and drought-resistant plant a try. And while I haven’t seen Jerusalem sage at local nurseries yet, I found many online resources where the plant is readily available.

As always, keep an eye out next time you are walking. Who knows what intriguing things you might see! With late summer and fall or the horizon, what plant mystery will we solve next?

Notes

1–The genus Pholmis has many varied species, so make sure to research thoroughly those other than the Phlomis fruticosa discussed here. Required growing conditions will vary per species.

2–Xeriscaping is type of landscape design that keeps water conservation in mind and requires minimal supplemental water once plants are established.

Resources and Additional Information

For more on Jerusalem sage, see NC Extension Gardener Plant Toolbox.

https://plants.ces.ncsu.edu/plants/phlomis-fruticosa

For more information on water-wise landscape design, check out NC Department of Environmental Quality’s site on xeriscaping.

https://www.deq.nc.gov/environmental-assistance-and-customer-service/nc-green-travel-documents/xeriscape/download

For more on native and non-native drought-resistant plants, see NC Botanical Garden’s plant list as well as our former blog post “Ten Plants That Can Take the Heat.”

Gardening for a Drought: North Carolina Native Plants to the Rescue

https://durhammastergardeners.com/2022/05/18/ten-plants-that-can-take-the-heat/

Article Short Link: https://wp.me/p2nIr1-4Nj

Assistant plant detectives Baby and Cole are always on the case. (Image credit: Melinda Heigel)

*A bounty of beautiful tomatoes.* (Image credit: Kathryn Hamilton)

By Kathryn Hamilton, NC State Extension Master Gardener^SMvolunteer of Durham County

This summer, Durham County is one of eight counties in North Carolina to participate in a state-wide tomato trial. We will compare yields of three tomatoes created by NC State against ‘Cherokee Purple’ regarded for its flavor, productivity, and resistance to cracking. Check out our page on the blog called “Tomatoes on Trial” The 2024 Tomato project here. While we are busy conducting the trials, here are some tips to help you maximize your harvest.

Water Carefully and Consistently

Cracking occurs when tomatoes get a huge amount of water all at once (as an example, after a major storm) causing the fruit to swell and the skin, because it cannot grow fast enough, to crack. Calcium travels from the soil through water, and if water is insufficient the calcium never reaches the fruit, resulting in blossom end rot. This condition usually affects the first tomatoes and can be reversed with regular watering.

(Left to right) Cracking often occurs after a heavy rain. The skin can’t keep up with the swelling of pulp and consequently splits. (Image credit: Mary Knierim) Blossom end rot is preventable by consistent watering which brings calcium up into the fruit. (Image credit: NCSU Plant Disease and Insect Clinic)

During the growing season, tomatoes need 1 – 2” of water per week, the equivalent of two to four gallons. One way to measure this is to time how long it takes to fill a two-gallon container, then count along each time you water. To reduce the incidence of soil-borne diseases splashing on to the tomato vine, water at soil level, preferably in the morning to allow any leaves to dry out during the day. It is best to water deeply once or twice a week to encourage root development. The soil should be damp 6 – 8” down. Use a water meter, a trowel, or your finger to get a “reading.”

Mulch Your Bed, or at Least your Plants

Mulching carries multiple benefits. It keeps the soil moist and can help reduce both weeds and the spread of soil-borne diseases. Organic options include dried grass clippings, which have not been treated with an herbicide, and shredded cardboard or newspaper. Other options include hay or straw, and leaves (provided they are not from the black walnut tree). Avoid sawdust and wood chips which will draw nitrogen out of the soil as they decompose. There are pros and cons regarding plastic mulches. Black can heat up the soil too much; clear can foster the growth of weeds. Research at Clemson University has shown that red mulch (now available in small quantities at some on-line garden retailers) can boost tomato yields by 20 percent while conserving water and controlling weeds.

(Left to right) Grass, untreated with herbicide, is an excellent mulch; Red plastic mulch developed by Clemson University and the US Department of Agriculture is now available in smaller quantities from some on-line retailers. Use it to increase yields, prevent weeds, and retain moisture. This is not to be confused with red-dyed wood mulch. (Image credits: Kathryn Hamilton)

Feed Wisely

A three-number code on each bag of fertilizer identifies its composition. The first number relates to nitrogen (think greenery); the second to phosphorous (flowers and fruit formation), and the third, potassium (contributing strong stems and disease resistance). Once the plant has started to set fruit (usually 4 to 6 weeks after planting) side dress the tomatoes with a balanced fertilizer (i.e. 8-8-8), or one in which the first number is smaller than the others. An over-abundance of nitrogen will promote vine growth at the expense of fruit. Among the best analyses for tomatoes, according to the University of Missouri are 8-32-16 and 6-24-2. Follow package directions in terms of fertilizer amount and frequency.

Practice Rigorous Maintenance

To reduce contamination by soil-borne diseases, prune the bottom leaves up by as much as a foot. Be rigorous in removing diseased and rotting leaves.

*Pruning leaves up to 18″ from the ground reduces transmission of soil-borne diseases*. (Image credit: Kathryn Hamilton)

Diatomaceous Earth

Diatomaceous earth is a highly porous powder made from the sediment of fossilized algae. Sprinkled at the base of the plant and on the leaves and fruit it can help control a variety of insects. Diatomaceous earth is not a poison; it causes insects to dry out and die by absorbing the oils and fats from their exoskeleton. To be effective it must remain dry and undisturbed. The Food and Drug Administration lists diatomaceous earth as “generally recognized as safe.” Food-grade diatomaceous products are “purified.” It is generally available in garden centers, and sometimes even at stores such as Walmart.

Fungicides

Fungicides can be helpful as both a protectant and preventative against fungal disease. Fungicides labeled for use on tomatoes and containing either chlorothalonil or mancozeb can reduce the spread of fungal leaf diseases. Copper-containing fungicides protect plants from leaf diseases caused by bacteria and some fungi. Preventative activity occurs when a fungicide is present on or in the plant before the pathogen (disease) arrives or begins to develop. Preventative fungicides can still be used if the disease is present at low levels, since they will prevent new infections from occurring on the unaffected leaf tissue. A curative situation occurs when the fungicide stops the early growth of the pathogen. But, it must be applied within 24 to 72 hours of the infection. Fruit treated with some fungicides can be eaten immediately; other fungicides require a waiting period. As with any chemicals, read the label carefully before use.

Prune for Air and Yield

In terms of yield, pruning suckers is a choice. Cutting them out will yield fewer but bigger tomatoes. Leaving them in will increase quantity. However, pruning suckers will help to increase air flow and potentially decrease air-borne disease. This can be particularly helpful if, like most tomato fans, you over-plant your garden bed.

*Suckers sprout from where the stem and branch of a tomato meet. Bonus: they will root in water to produce a new tomato plant* (Image credit: Kathryn Hamilton)

Growing tomatoes can be both challenging and rewarding. To help with the challenging issues, please find additional information in the following links.

Resources and Additional Information

Learn more about organic and inorganic mulch as well as cover crops to optimize tomato growth. Mulches for the Home Vegetable Garden (UVA) https://www.pubs.ext.vt.edu/content/dam/pubs_ext_vt_edu/426/426-326/SPES-256.pdf

This article covers tips for the home gardener and summarizes common problems related to growing tomatoes. How to Grow Tomatoes in your Garden (Utah State)
https://extension.usu.edu/yardandgarden/research/tomatoes-in-the-garden

A nice review of the disease cycle and when to use preventive or curative fungicides.
Preventive vs Curative Fungicides (Iowa State) https://crops.extension.iastate.edu/cropnews/2008/07/preventative-vs-curative-fungicides

This resource provides an overview of how to diagnose tomato diseases and treatment options. A Valuable Resource on Tomato Diseases (NCSU)

https://vegetables.ces.ncsu.edu/tomatoes-diseases/

Article Short Link: https://wp.me/p2nIr1-4BD

Extension Master Gardener Volunteers of Durham County

Category: sustainable gardening

Plant Detective: Investigating the Intriguing Jerusalem Sage Plant