At first glance, you might think that the rue plant is just an ordinary blue-green bushy herb with flowers waving above the foliage, but you’ll soon discover that it has some distinguishing characteristics worth noting.
When the rue plant's tough, fleshy leaves are lightly disturbed, it gives off a fruity smell. But be aware that when the plant is crushed, it emits a powerful musk odor. So, what is there to love about rue? Surprisingly, the rue plant is a natural choice to add to a butterfly garden because, in addition to being beautiful, it is a host plant for the black swallowtail, giant swallowtail, and other butterflies.
Native to Southern Europe and the Balkan Peninsula, rue plants have been cultivated since at least the 16th century. They are among the oldest known plants cultivated for medicinal and culinary use, but today are grown strictly as ornamental plants because of their known toxicity to humans. Rue plants are, however, still beloved for their bluish leaves and tolerance to dry soil conditions.
This perennial herb was once used medicinally. Today, rue is known to be toxic to people and animals when consumed in large quantities. Always wear gloves when handling rue because the oils on the leaves can skin irritation similar to a poison ivy reaction.
DEAN SCHOEPPNER
Rue Overview
Where to Plant Rue Plant
Rue’s finely cut blue-green foliage makes it an attractive clumping plant for rock gardens with full-to-part sun conditions. In fact, rue often grows wild in vineyards and gravel pits on rough, stony ground. Rue also makes a welcome addition to pollinator gardens, butterfly beds, and deer-resistant borders. However, while rue is short-lived, it self-seeds. Remove its flower heads before they set seed to avoid unwanted plants.
In edible gardens, rue’s strong fragrance can deter pests from some plants (like raspberries, alpine strawberries, and figs), but avoid planting rue near tomatoes, basil, cabbage, cucumbers, or sage. When planted near these, the herbaceous perennial can inhibit growth and alter the flavor of some fruits, vegetables, and herbs.
How and When to Plant Rue Plant
Plant rue seeds outdoors in the spring so your plants have the entire growing season to develop strong roots. Sow the seeds on top of the soil and sprinkle them lightly with soil or press them down gently with your fingers. They will need light to germinate. The germination process for rue plants can take up to 4 weeks, so it’s important to be patient. Once the seedlings emerge, thin or transplant them to allow one foot of space between plants.
Rue Plant Care Tips
Rue is so easy to grow that it can easily become a nuisance in the garden with its ability to self-seed.
Light
Rue grows best in full sun and should receive at least six hours of direct sunlight daily. The plant also tolerates part shade, however, it will produce fewer flowers in the shade.
Soil and Water
Rue grows best in moderately fertile, well-drained soil, but will tolerate dry and rocky soil. Rue tolerates drought, so like other drought-tolerant perennials, you’ll only need to water the plant when dry weather lingers.
Temperature and Humidity
The rue plant is extremely drought-tolerant—especially when planted in a sheltered area with loose, lime-rich soil. It prefers temperatures between 65°F and 75°F and is tolerant of humidity as long as its soil has good drainage.
Fertilizer
Rue generally does not require fertilizer if it is planted in rich soil. If your soil is poor, add a completed balanced slow-release fertilizer once each spring, following product label instructions.
Pruning
In early spring, prune stems back to 6 to 8 inches to encourage bushier growth and to keep the rue plant from getting too leggy.
Pests and Problems
Rue is seldom affected by insects or diseases. It is a hardy plant that is deer-resistant and attracts pollinators. Root rot may occur if rue is overwatered or planted in poorly drained soils.
How to Propagate Rue Plant
The rue plant is usually propagated by seed and germinates after a cold period. You can also take stem cuttings from established plants and root them in a shady place or container and then transplant them.
Types of Rue Plant
DENNY SCHROCK
'Jackman's Blue' Rue
Ruta graveolens ‘Jackman's Blue’ is noted for its vivid blue foliage. Like common rue plants, it bears yellow flowers throughout the summer. It grows 2-3 feet tall and wide in zones 4-10.
DENNY SCHROCK
Fringed Rue
Ruta chalepensis L. (commonly known as fringed rue or Egyptian rue) is named for its fringed yellow flowers. They appear in spring amidst blue-green foliage that closely resembles that of common rue. This rue plant is a favorite host plant of swallowtail butterfly larvae. It grows 2-3 feet tall and 2 feet wide in zones 8-10.
Companion Plants for Rue Plant
Rue doesn’t seamlessly coexist in all gardens because the phytotoxins released by the rue plant foliage inhibit growth for some plants and may alter their flavor. For this reason, do not grow rue around basil, sage, cabbage, cucumbers, and mint. However, companion planting rue with the following plants can be beneficial.
Onions
Growing onions (a staple ingredient for flavoring many recipes) with rue can prevent onion fly larval damage. The rue plant’s scent deters the onion fly from laying its eggs near the vegetable. Like rue plants, onions do best in loose, well-drained soil. To sow onion seeds outdoors, plant them 3/4 inch deep in loose, moist soil and thin them to 3-4 inches apart after seedlings emerge. Plant onion bulbs or sets in the garden two to three weeks before the average last frost date.
Roses
Planting rue plants next to roses, one of the most popular flowers in the world, will help deter aphids from your rose garden. Roses should be planted after the last frost in the spring or in fall (at least six weeks before your average first frost). Dig a hole big and wide enough to fit the entire root system—roses don't like to be crowded. Also, plant rose bushes at least 3 feet apart to allow for growth.
Raspberries
Growing rue plants next to raspberry plants will help keep damaging insects (such as aphids and beetles) away from your raspberries. Plant raspberry canes 20 inches apart and in rows 5 feet apart. Raspberry plants are hardy in USDA Zones 3-9, so once they’re established, you don’t have to worry about replanting them each year.
Frequently Asked Questions
- Does rue keep mosquitos away?Rue has a long history of being used to repel insects. Its strong odor often deters pests. A recent study revealed that the essential oil of rue showed insecticidal activity against mosquito larvae.
Rue has a long history of being used to repel insects. Its strong odor often deters pests. A recent study revealed that the essential oil of rue showed insecticidal activity against mosquito larvae.
- Are rue plants invasive?While rue plants readily self-seed, they are not considered invasive. That said, they have escaped cultivation and are considered a noxious weed in some regions. To control the spread of your rue plants, remove the seed heads before they disperse their seeds.
While rue plants readily self-seed, they are not considered invasive. That said, they have escaped cultivation and are considered a noxious weed in some regions. To control the spread of your rue plants, remove the seed heads before they disperse their seeds.
- What can rue plants be used for?If you’re looking to add color to your landscape, rue’s blue-green leaves make an attractive addition. It is also extremely easy to grow—even in poor soil. What's more, the rue plant’s flowers and seed heads can be easily dried to add a light airy effect to dried floral arrangements.
If you’re looking to add color to your landscape, rue’s blue-green leaves make an attractive addition. It is also extremely easy to grow—even in poor soil. What's more, the rue plant’s flowers and seed heads can be easily dried to add a light airy effect to dried floral arrangements.