Rue: flower, growing & uses

Rue is a beautiful, undemanding and evergreen perennial with lots of health benefits.

As early as the Roman Empire and throughout the Middle Ages, rue (Ruta graveolens) was a popular spice and, most importantly, a common medicinal herb. Some traditional rue recipes from these times have even been preserved. Nowadays, rue is mainly cultivated as an ingredient used in grappa (a kind of liqueur), as well as a heat and drought tolerant aromatic herb and as a decorative perennial in home gardens.

Rue: origin and properties

The plant known to us as common rue originated in the eastern Mediterranean and spread from there, so that nowadays it can be found all over the world. The meaning of the Latin name can be off-putting at first: Ruta means something like “bitter-tasting herb” and the appendix graveolens, meaning “heavy or foul smelling”, only adds to this. Ruta graveolens is a woody, evergreen shrub that usually grows to around 50cm high. Its pinnately lobed leaves are up to 11cm long and look particularly striking because of their dark blue-green colouring.

The leaves cause phototoxic reactions and can cause severe skin rashes, so be careful when growing at home and make sure to wear gloves when handling them. The rue flowers are a real hit with bees and other insects. They form yellow-green umbel shaped flowerheads, usually between June and October. In contrast to the strong-smelling leaves, the flowers have barely any fragrance. Even though the herb of grace originates from the Mediterranean region and copes well with heat, it also tolerates temperatures as low as -28°C. Therefore, it is usually no problem to grow common rue as a perennial at home.

How to plant and care for rue

Rue likes a sunny and relatively dry location with a loose, nutrient-poor but lime-rich soil. If your garden soil is particularly humus-rich, loamy or clay-rich, mix in some sand and lime. This improves drainage and makes the soil looser, less nutrient-rich and more alkaline.

Sow rue indoors in seed trays from March or directly outdoors from April. Sow the rue seeds about 0.5 to 1cm deep. They germinate at an optimal temperature of 10 to 18°C within 2 to 3 weeks. Space the rue seeds 30cm apart in the garden bed.

Tip: Ruta graveolens grows well in pots. Our Plantura Organic Herb & Seedling Compost is perfect for this. Mix the compost with a little lime and a third sand or perlite. Use a pot with a volume of at least 10 litres. Overwinter potted rue in a frost-free location as there is a greater risk of the roots in a container freezing and the plant dying.

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Watering rue

Rue has a moderate water requirement so water your plants regularly. However, perennial rue also tolerates the soil drying between watering. Straight after planting, make sure to water your plants often until the plant is well established.

Fertilising rue

Too much fertiliser will do this undemanding plant more harm than good. For rue plants growing in a container, you may need to repot the plant in fresh soil. Add a small amount of slow-release fertiliser, such as our Plantura All Purpose Plant Food, to give the plant a long-term supply of nutrients until the next repotting.

Pruning rue

Pruning is also not strictly necessary. If at all, prune in spring before resprouting. In February or March, cut shoots back so far that a pair of buds remains. The plant will then sprout again and continue to grow compactly. In autumn, you can also cut back potted rue plants that are sheltered from frost over winter.

Is rue winterhardy?

Herb of grace plants usually tolerate temperatures as low as -28°C, which is why rue can survive as a perennial in our gardens. Overwinter potted common rue in a frost-free location, ideally in a light and cool place, as its roots are less well protected than those of plants in the ground.

How to propagate rue

It is easy to propagate rue by seed. Collect the brown seed capsules in autumn, preferably in rather dry weather. Remove the black, crescent-shaped rue seeds from the capsules and dry for two days. Store in a cool, dry place over the winter. In spring, sow the seeds as described above.
Rue can also be propagated by dividing the plant or from stem cuttings. The best time for division is in autumn.

Take cuttings of young, half-woody shoots in summer or autumn. Remove the lower leaves and put the cuttings into seedling compost mixed with sand in a 1:1 ratio. Keep the soil moist, but not wet. Keep the cuttings indoors for the first winter in a cool, bright place at around 20°C. The following spring, transplant outside.

Is rue poisonous?

Rue’s properties are usually described as beneficial to health, but it is important to be very careful when growing and using them. This is because the rue leaves have phototoxic properties. This means that they can cause severe irritation and blister-like rashes when they come into contact with the skin. Therefore, always wear gloves when working with rue and wash your hands and arms thoroughly afterwards. When using rue herb, use it very sparingly, as it is poisonous if consumed in large quantities. Pregnant women in particular should refrain from ingesting rue, as it can trigger early labour pains and thus induce miscarriages.

Harvesting, use and properties of rue

It is advisable not to harvest the plant much or at all in the first year of cultivation so that it has a chance to get well established. From the second year onwards, harvest fresh leaves from May onwards. For brewing rue tea, cut back individual stems to 10cm above the ground and dry them whole. The healing properties of rue are said to be antispasmodic, anti-inflammatory and blood pressure lowering. Ruta graveolens can be used for arthritis, joint pain, headaches and toothaches as well as varicose veins and sleep disorders. You can also use the herb of grace as a culinary herb for hearty dishes and stews. However, use rue very sparingly, as its strong, bitter taste is very overpowering and it can cause discomfort in larger quantities. When considering using rue for medicinal purposes, discuss the matter with your doctor before consumption.

Rue as a rat and cat repellent: Rue leaves give off an intense scent that is sometimes perceived as unpleasant. Some insect pests, rats and cats also dislike the smell. So, if you want to keep these animals away, you can plant rue to repel cats and rats.

Another shrub that can be grown both as an ornamental plant and for its medicinal uses is mugwort. Read our mugwort guide to find out more.