Jerusalem sage is an attractive, shrubby perennial with fuzzy green-gray leaves and whorls of yellow flowers. Here’s everything you need to know about planting and caring for this desert-adapted shrub.
Jerusalem sage (Phlomis fruticosa) is a medium size plant native to dry areas of the Mediterranean, but now has a wide distribution which includes the desert southwest.
(Some sources consider it a perennial while others consider it a shrub. I’m on the fence and so will call it a shrubby perennial. 😉 )
It is semi-woody and has fuzzy green-gray leaves with almost white undersides. Whorls of cheerful lemon-yellow flowers line the flower spikes, looking a little bit like snapdragons and smelling a bit like cloves.
This resilient, low-maintenance plant is happy in a wide variety of climates. In the southwest, it grows in full sun or part shade, needs minimal irrigation, and can survive temperatures down to 15℉.
Its flowers attract birds, bees, and butterflies. The seed heads, if left on, provide a winter food source for birds.
Why I Like This Plant
- Evergreen with attractive yellow flowers
- Tolerates extreme heat and cold
- Low maintenance
- No thorns, low litter, non-toxic
- Attracts birds, bees, and butterflies
- Deer and rabbit resistant
Things to Watch Out For
While this soft fuzzy plant invites touching, some people find the small hairs irritating, so it’s advisable to cover up when planting or pruning.
Optimal Growing Conditions
If you’re thinking of adding Jerusalem sage to your garden, you need to find a suitable place that will keep your plant healthy and looking good… while minimizing maintenance for you.
Here are the key factors to keep in mind.
Temperature
Jerusalem sage is very resilient and can be grown in USDA Hardiness Zones 7 – 11. It tolerates desert heat and is cold-hardy down to 15℉. It’s considered evergreen in zones 8 – 10 (which includes Tucson and Phoenix), but in colder zones, it will survive but die back during the winter.
Sun Exposure
Plant Jerusalem sage where it gets either full sun or part shade. Don’t plant along a hot wall, as it does not like reflected heat. And don’t plant in full shade, where it tends to get leggy.
Size and Growth Rate
Jerusalem sage is considered a moderate grower that generally reaches a mature size of 4’ wide by 4’ tall.
Soil
It’s not particular about soil and grows well in any native desert soil, provided it’s well-draining.
Other Location Considerations
While you can grow this anywhere you would grow a perennial or a small shrub, it works especially well in an herb garden. It can also be grown in a container.
Jerusalem Sage:
The Essentials
| Common Name | Jerusalem sage |
| Scientific Name | Phlomis fruticosa |
| Origin | Mediterranean |
| Plant Type | Shrubby perennial |
| USDA Zones | Zones 7 – 11 |
| Cold Hardy | To 15℉ |
| Flower Color | Yellow |
| Flower Season | Spring, summer |
| Mature Size | 4’ high x 4’ wide |
| Growth Rate | Moderate |
| Sun Tolerance | Full, part sun |
| Water Needs | Low |
| Pests & Diseases | Root rot |
| Garden Friendly | No thorns, non-toxic |
| Cautions | Irritating hairs |
| Wildlife | Attracts hummingbirds, butterflies, bees Deer, rabbit resistant |
How to Plant
The rule of thumb when planting any perennial in the desert is to dig a hole twice as wide as the root ball but no deeper. Amending the soil is not recommended. Counterintuitively, backfilling with the same native soil you just dug up helps your plant develop a stronger root system.
When to Plant
The best time to plant Jerusalem is in the fall. This gives it three seasons to grow roots and get established before the following summer.
The second best time is in spring, the earlier the better. This still gives your plant time to get established before the intense heat of June arrives.
How to Care for Jerusalem Sage
Whether you’ve recently planted a Jerusalem sage or have an existing one in your yard, here’s how to take care of it to keep it healthy and looking its best.
How to Water New Plants
Once you’ve got your Jerusalem sage in the ground, watering is your most immediate concern. Here is the recommended watering schedule for new shrubs planted in the spring or fall.
| Weeks 1 & 2 | Every 3 – 4 days |
| Weeks 3 & 4 | Every 6 – 7 days |
| Weeks 5 & 6 | Every 7 – 10 days |
| Weeks 7 & 8 | Every 10 – 14 days |
After week 8, gradually extend the time between waterings.
How to Water Established Plants
As your plant gets established, there are two watering factors to consider.
- First is how often to water. This will vary with the seasons.
- Second is how much water to give your shrub with each watering. This depends on the current size of your plant.
Take care not to overwater Jerusalem sage which can lead to root rot.
To determine the ideal watering schedule for Jerusalem sage or any desert shrub you’ll find everything you need to know, including easy-to-use charts, at How to Water Desert Shrubs: How Often? How Much?
Should You Fertilize?
While most native plants don’t need fertilizing, Jerusalem sage is not native and can benefit from an application of fertilizer once in the spring.
How to Prune
Jerusalem sage looks best when it gets a severe pruning in the late winter. Additionally, you can dead-head the spent flower spikes. This is optional, but will encourage more blooms.
Jerusalem Sage Cultivars
There are a few varieties of Jerusalem sage that you may encounter when shopping.
Phlomis fruticosa ‘Grande Verde’ is a popular cultivar that has noticeably larger and green leaves than the parent plant.
Phlomis fruticosa ‘Nana’ is a robust dwarf version that tops out at 2 feet by 2 feet.
Don’t Confuse Jerusalem Sage With…
There are two very similar plants with the common name Jerusalem sage. Phlomis russeliana is a smaller plant that is less tolerant of heat and sun, which makes it less suitable for the desert.
There is also a plant called small Jerusalem sage (Phlomis lantana) that is only 1 foot tall but otherwise similar in hardiness and care.
Plant Lover Facts
Jerusalem sage is not a true sage. It’s more like a botanical cousin since they are both members of the mint family (Lamiaceae).
Since Jerusalem sage grows in the desert, you might be surprised to learn that it’s naturalized in parts of the United Kingdom where it’s a very popular landscape plant. Talk about versatility!
There’s some debate as to whether Jerusalem sage is edible. I’ve read that leaves and roots are edible, but not on sites that I would trust with my life.
However, the entire genus has a long history of traditional medicinal uses including for treating diabetes, ulcers, hemorrhoids, inflammation, and wounds. Researchers have found some other closely related Phlomis species to have anti-inflammatory, antimicrobial, and antioxidant properties.
A chemical analysis of Jerusalem sage found it contained 44 biologically active compounds which have potential medical value.
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Author Bio
Deane Alban is the creator of Southwest Gardener. She is a science writer with a bachelor’s degree in botany from the University of South Florida. Gardening is her lifelong passion. She’s been gardening in Tucson for 15 years.
Photo Credit
Stan Shebs, CC BY-SA 3.0, Wikimedia