Chinese rhubarb (Rheum palmatum)
Discover Chinese rhubarb (Rheum palmatum), a dramatic herbaceous perennial reaching 10 ft tall, prized for huge foliage and summer flower plumes.
Complete Plant Information
Overview
Rheum palmatum, widely known as Chinese rhubarb, is a spectacular, imposing plant perfect for adding architectural drama to the garden. It quickly establishes a massive presence, featuring rounded, highly lobed basal leaves that can span several feet wide, forming a bold foliage mound. This plant stands apart from its smaller culinary relatives because it is primarily cultivated for its immense ornamental capabilities and historical medicinal value, not for edible leaf stalks.
As a rhizomatous perennial, Chinese rhubarb develops a sturdy structure capable of supporting large plumes of pink to red flowers from May through July. It demands space to truly shine, growing up to 10 feet tall in optimal conditions. Gardeners looking for a low-maintenance, high-impact specimen that thrives in moist, rich soil will find Rheum palmatum an exceptional addition to the landscape.
Fast Facts
- Plant Family: Polygonaceae
- Plant Type: Herbaceous perennial
- Native Range: Northwestern China
- Hardiness Zones: USDA Zones 5-7
- Size at Maturity:
- Height: 6-10 ft
- Spread: 4-6 ft
- Bloom Time: May to July
- Bloom Description: Pink to red
- Sun Exposure: Full sun to part shade
- Water Needs: Medium
- Maintenance Level: Low
How to Grow
For optimal establishment, plant Chinese rhubarb in the early spring. It thrives best in organically rich, moderately fertile soils that maintain even moisture but demand excellent drainage. While it tolerates a range of light, ensure it receives full sun, though afternoon shade is beneficial in the hottest summer climates.
Watering is crucial; unlike common rhubarb, Rheum palmatum shows increased sensitivity to both drought and excessive heat, especially outside its preferred Zones 5-7 range. Apply mulch heavily around the base to keep the extensive root system cool and conserve soil moisture throughout the growing season.
Propagation of established plants is easiest done via division of the rhizomes, ideally performed in early spring before active growth begins. Although seeds can be planted in the fall, division provides faster, more reliable results for increasing your collection of this imposing plant.
Landscape Uses
The sheer scale of Rheum palmatum makes it an unparalleled bold ornamental specimen or accent plant. Due to its massive size—up to 10 feet tall—it requires significant space and works well when planted in large borders where it can act as a structural backdrop. It is also highly effective near the margins of water features, such as streams or ponds, provided the soil remains moist and well-drained.
When integrating this plant into a design, consider pairing it with plants that contrast its leaf texture or color, such as fine-textured grasses or darker foliage shrubs that can handle similar moisture regimes. Beyond its aesthetic appeal, Chinese rhubarb serves traditional herbal/conventional medicinal uses, adding a functional layer to the ornamental border. Ensure you place Rheum palmatum where its huge basal leaves can spread without crowding neighboring plants.
Standout Features
Flower Qualities
- Showy
Noteworthy Characteristics
Rheum palmatum, commonly called Chinese rhubarb, is a rhizomatous perennial with a large rootstock and thick leafstalks that typically grows to 6-10’ tall. Unlike its culinary cousin, Chinese rhubarb is valued primarily as an ornamental appreciated for its huge rounded leaves and feathery plumes of summer flowers, or for its medicinal root properties. The palmately-lobed, dark green basal leaves can reach 2-3’ wide, forming a large domed mound, while large plumes of tiny, pink to red flowers rise dramatically above the foliage on thick stems.
Tolerances
Potential Problems
Chinese rhubarb generally exhibits low susceptibility to serious insect or disease issues, but proper site selection is key to long-term health. The most significant potential problem is crown rot, which occurs if the soil lacks adequate drainage, especially during wet winters or springs. Good drainage is paramount for the rhizomes of Rheum palmatum.
Gardeners should remain watchful for potential pests such as borers, beetles, or the rhubarb curculio, though serious infestation is uncommon. Additionally, leaf spots can sometimes appear on the large foliage; however, they rarely impact the plant’s overall vigor or ornamental quality significantly enough to warrant chemical intervention.
Frequently Asked Questions
What hardiness zones is Chinese rhubarb suitable for?
Chinese rhubarb (Rheum palmatum) is best suited for USDA Zones 5 through 7. Best growth is achieved in these zones, as the plant dislikes the intense heat found in Zones 8 and 9.
How large does Chinese rhubarb grow?
This impressive perennial commonly reaches heights between 6 and 10 feet, with a spread usually covering 4 to 6 feet at maturity.
When does Chinese rhubarb bloom?
Rheum palmatum produces its bloom display from May through July, featuring feathery plumes of pink to red flowers rising well above the foliage.
What sun exposure does Chinese rhubarb need?
Chinese rhubarb prefers a location receiving full sun to part shade. Providing some afternoon shade is often recommended in very hot climates to prevent stress.
Conclusion
The dramatic size and texture offered by Chinese rhubarb make it an indispensable choice for gardeners seeking architectural interest and low-maintenance structure. Its seasonal pink-red flowers add a beautiful, airy contrast to the dense foliage mass of Rheum palmatum. Evaluate your site conditions carefully, ensuring rich, well-drained soil availability within USDA Zones 5-7 before planting this magnificent specimen.
Companion Planting
Selecting the right companions for Rheum palmatum involves choosing plants that enjoy similar moisture levels while offering textural contrast. Given its massive scale, lighter, airier perennials complement the heavy, rounded leaves of Chinese rhubarb beautifully. Consider planting it alongside tall ornamental grasses which sway in the breeze, softening its imposing presence.
Plants that thrive in moist, rich soil are ideal partners. Hostas, though shorter, can fill in the foreground beneath the canopy of Rheum palmatum, provided they receive adequate shade protection if the rhubarb is sited in full sun. Ensure that any companions do not compete heavily for the root zone, as this perennial dislikes having its roots disturbed once established.
Propagation Tips
Propagation for Rheum palmatum is most effectively managed through the division of its substantial rhizomes. This process should be undertaken in the early spring just as growth is beginning, allowing the divided sections the entire growing season to reestablish a strong root system. Dig carefully around the established clump only as much as needed to sever a viable section, ensuring each division has both roots and at least one healthy growth bud.
If starting from seed, sow the seeds of Chinese rhubarb in the fall, allowing them the natural stratification period of winter to encourage spring germination. While seed propagation is possible, it takes significantly longer to achieve the imposing size for which Rheum palmatum is known compared to established rhizome divisions.
