durham – Page 4 – 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)

By Deborah Pilkington, NC State Extension Master Gardener^SM volunteer of Durham County

Container gardeners, me included, give a lot of thought to choosing which plants will go into the containers. But not a lot of thought is given to the containers themselves. Yet, to have a successful container garden in full sun, shade, or anywhere in between, the choice of pot is as important as the choice of plant. So, for the next few minutes, we’re going to look at factors that should be considered for container choices, especially in our newly-designated hardiness zone 8.

Porosity

*Examples of porous pots*. (Image credit: Deborah Pilkington)

Some containers, such as the familiar terra cotta (“baked earth” in Italian) are very porous, meaning the pot draws water from the potting media through its walls. Other porous materials include hypertufa, unglazed ceramic, and clay. Because of this, these porous pots may require more frequent watering, something to think about if they are going to be in full sun. Less porous choices would be wood or concrete, and the least porous pots are made of metal, fiberglass, plastic, or glazed ceramic. That means they are going to help the potting mix conserve water.

Size

The smaller the pot size, the more frequently it will need to be watered, sometimes more than once a day. A larger container is going to be heavier and less likely to tip over. Larger containers will require less frequent watering but can be a bear to move from location to location…unless you own one of these (see the photo below). And the cost of filling the container with potting mix is also a consideration.

*The difficulty of moving very large pots!* (Image credit: Deborah Pilkington)

Fragility

If a container is fragile and susceptible to cracking in cold temperatures, it will need to be moved to a sheltered area for winter. Terra cotta, clay, unglazed ceramic, and hypertufa are all fragile materials. The sturdiest are metal, plastic, concrete and wood.

Heat Holders

Metal containers, and dark-colored containers are heat holders in full sun. They can even be hot to the touch! Potting mix in these containers can rise to well over 100°F. Keeping roots well-watered, unless you are growing cactus, is a must.

Shape

If you are going to grow a shrub or tree in a container, at some point the plant will need to be lifted from the container to be root pruned—an onerous but necessary task. So, for shrubs or trees you want to choose a container that is wider at the top (below on the right) rather than narrower (below on the left) to make lifting easier.

(Left) This container is more narrow at the top and would make it difficult to remove a shrub that had grown in the pot. (Right) In contrast, this pot is wider at the top than the bottom and it would be easier to remove a shrub that had been grown in the pot. (Image credit: Deborah Pilkington)

Drainage

Good drainage is a must in container gardening. If the container doesn’t have drainage holes, you can add them using a drill and the appropriate drill bit. And to ensure correct drainage, don’t put anything in the bottom of your container but soil mix. Adding gravel or covering the hole with broken terra cotta not only defeats the purpose of ensuring drainage, but it also raises the level of the perched water table, moving the level of saturated soil even higher in the container and closer to the roots.

*Drilling holes in metal containers at Cocoa Cinnamon Demo Garden on Geer Street.* (Image credit: Deborah Pilkington)

For gardeners with limited space, especially the newcomers to Durham’s condominiums and apartments with balconies, container gardening can bring some beauty and food to your home. For urban container gardening inspiration, visit the International Award-Winning Master Gardener^SM Container Demonstration Garden at Cocoa Cinnamon at Foster and Geer streets in Durham.

*Get more ideas on container gardening by visiting the Cocoa Cinnamon Demonstration Garden at 420 West Geer Street in Durham, NC.* (Image credit: Deborah Pilkington)

Resources and Additional Information

Check out the links below to learn more about plant hardiness zones including the history and factors used to determine the hardiness zone of an area. What does this really mean for North Carolina gardeners?

2023 USDA Plant Hardiness Zone Map | USDA Plant Hardiness Zone Map

Gardening Association of North Carolina – 2023 USDA Plant Zone Update (gaonc.org)

AN ILLUSTRATED HISTORY OF AMERICA’S PLANT HARDINESS ZONES (With a Closing Look at North Carolina) | by Tom Packer

For more information on perched water tables and soilless media check out the below online guide about drainage for containers.

How to Improve Drainage in Plant Pots, The Proper Way to Do It! – Deep Green Permaculture

If you want to take a deep dive into the physics of water movement in soilless media and media components, visit the following links.

Growing Media (Potting Soil) for Containers | University of Maryland Extension (umd.edu)

Homemade Potting Media (psu.edu) — How to make your own potting media

Learn more about choosing pots with the in-depth article below.

Containers, Pots, and Planters: What Material Is Best? (gardenerspath.com)–

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