Thorow-wax Bupleurum rotundifolium

Water

Hare's ear (Bupleurum rotundifolium) prefers consistent moisture but does not like to be waterlogged. It's best to water this plant deeply once a week, allowing the soil to dry out slightly between waterings. Depending on weather conditions and soil drainage, this may translate to about 1 inch of water weekly. During periods of drought or extreme heat, you may need to increase the watering frequency. In general, use a soaker hose or drip irrigation to provide water directly to the root zone, reducing moisture on the foliage and preventing fungal diseases.

Light

Hare's ear thrives in full sun to partial shade. The best spot for this plant would be a location where it can receive at least 6 hours of sunlight per day. If you’re growing it indoors, place it near a south-facing window to ensure it gets ample light.

Temperature

Hare's ear does well in a wide range of temperatures, typically between 40°F and 85°F. It's important to protect the plant from frost, as temperatures below freezing can damage or kill it. The ideal temperature for promoting growth and flowering is around 70°F to 75°F.

Pruning

Pruning hare's ear is important to keep the plant looking tidy and to encourage bushier growth. Pinch back the tips of the stems in early spring to promote branching. Cut back any spent flowers after blooming to prevent self-sowing if desired. Pruning can be done as needed throughout the growing season to remove dead or yellowing leaves.

Cleaning

As needed

Soil

Hare's ear (Bupleurum rotundifolium) prefers well-draining soil with a slight lean towards alkalinity; a pH range of around 6.0 to 7.5 suits it well. To create the best soil mix, combine two parts garden soil, one part perlite or coarse sand, and one part compost. This mixture ensures proper drainage and provides a fertile growing medium with organic matter vital for the plant's health.

Repotting

Hare's ear typically doesn't require frequent repotting and can often be left undisturbed for several years. If growth has significantly slowed or the plant has become root-bound, repotting can be performed every 2-3 years during the spring season using a larger pot to accommodate the root system.

Humidity & Misting

Hare's ear enjoys moderate humidity levels but is quite adaptable to various humidity conditions. Maintaining a relative humidity of around 40-60% is generally sufficient for the plant to thrive. It's resilient and can tolerate variations in humidity, making it suitable for most indoor environments.

Suitable locations

• Indoor

  Ensure bright, indirect light, sparing water, and well-draining soil.

• Outdoor

  Choose a sunny spot, use fertile, well-draining soil, water regularly.

• Hardiness zone

  4-9 USDA

Life cycle

Bupleurum rotundifolium, commonly known as Thorow-wax, begins its life as a seed, which upon encountering favorable conditions such as sufficient moisture and temperature, germinates and develops into a seedling. As the seedling matures, it gives rise to a robust root system and a rosette of round, green leaves. The plant then undergoes vegetative growth, where stems elongate and leaves enlarge, preparing the plant for the next stage. As it enters the reproductive phase, Thorow-wax produces small, yellowish-green flowers typically arranged in an umbrella-like cluster known as an umbel, which after pollination develops into fruits. The fruits disperse seeds which conclude the plant's life cycle, allowing it to propagate the next generation. Throughout its life cycle, Thorow-wax completes its growth within one season, classifying it as an annual plant.

Propogation

• Propogation time

  Spring

• The most popular method of propagating Bupleurum rotundifolium, commonly known as hare's ear or thorow-wax, is by seed. Seeds are typically sown in late winter to early spring, allowing for a period of cold stratification which can enhance germination. Sow the seeds shallowly, at a depth of approximately 1/4 inch (about 6 millimeters), in well-draining soil and space them a few inches apart. They require light to germinate, so it's important not to cover them too heavily with soil. Keep the seedbed moist until germination occurs, which usually takes about 1 to 2 weeks. After seedlings have developed true leaves and are strong enough, they can be thinned out or transplanted to their final growing location.