Rumex Growing Guide


Common Name Rumex, Unicorn Rumex
Genus  Rumex
Species Trademarked variety, hybrid 
Family Polygonaceae
Life Cycle  Herbaceous Perennial (Exact hardiness unknown)
Format 32-cell plug tray
Plug Care Harden off and plant plugs promptly upon arrival. Do not leave them in the trays to become rootbound. Keep the growing medium evenly moist - not too wet, not too dry. In the first two weeks after planting, continue to water frequently while new roots establish. 
Netting / Staking Not typically required. The crop has flexible stems and abundant inflorescence/foliage movement; support usually not needed unless in an area that experiences extreme wind. In this case, use a layer or two of hortonova. 
Temperature Range We don't know how hardy it is, but we suspect it is hardy to at least zone 6, and possibly colder. They are quite productive and will keep producing new seed heads if you keep them cut back. 
Spacing Danziger recommends a planting density of 6 plants per square meter - assuming these plants were spaced evenly that would be about 15 inches between plants. They do get quite large and would be happy with a little more space if you have room. 
Soil Preference Moderate fertility, well-drained soils. Fairly forgiving of most average soils, but will perform best in a loamy soil with a good amount of organic material. Well draining soil is important. 
Day Length Long-day plant. If grown in a greenhouse outside of the regular growing periods it requires supplemental lighting to induce flowering (over 12 hours of light to maintain flower induction). When grown under natural daylength cycles they should flower mid-summer. 
Pinching After rosette establishment (~20 leaves), apply a single pinch to encourage branching / upright shoots. After the initial harvest is taken, the plant will send up an additional flush. 
When to Plant Plant in late spring after the soil has warmed and the threat of frost has passed for first year production. Can be planted later into the season, but that might limit the productivity in year one. 
Harvesting Harvest in the morning or later in the evening when the plant is best hydrated. It's very important to cut at the right stage. The “cut stage” is when the top of the inflorescence has just formed seed and a central stripe is visible - in the guide: “the indicator of how ripe the fruits are is the stripe in the center of the fruit - darker stripe equals more mature seed.” See photos in "Resources" link at the bottom of this page. Avoid harvesting too late (stem becomes heavy / loses color) or too early (shorter vase life). 
Post Harvest Care Cut stems should immediately be placed into clean, cool water. Use a floral preservative, and store in a cooler for best hydration. Be sure to remove any foliage that falls below the water line. With proper care you should see a 1-2 week vase life. See the "resources" link for some very specific details on a holding solution - this is typically more important when plants are being shipped across the globe, for our local market uses a simple holding solution should suffice. 
Diseases / Insects This variety has a high rust tolerance, but is susceptible to powdery mildew. Monitor readily for signs of foliar disease - spray with a general fungicide at the first sign of a fungal issue. Insect pests should not be an issue. 
Bailey's Notes

There are hundreds of species or Rumex. Some are kind of weedy and some are kind of cute. This one is a little of both. I don't think it will become a weed issue for you, especially if you cut the seed heads before they mature. It has been grown in several regions of the world and seems to be well behaved.  I grew this 2 years ago, curious about it's reseeding ability and it was not a problem.

Compared to wild forms, this hybrid Rumex is more uniform with full heads of bright green. Use it like you would use Lepdedium or Amaranthus. It has a certain carefree wildflower quality to it, or it could be used for its sleek green textural qualities in modern design.
Resources Danziger Culture Guide