Agriculture Reference
In-Depth Information
The genus
Rheum
contains 50 or so species, two of which are grown as vegetables: garden rhubarb (
R.
rhabarbarum
) and so-called false rhubarb (
R. rhaponticum
). Rhubarb is an herbaceous perennial that
already has a permanent place somewhere on the border of many home gardens. Leaf stalks are har-
vested every spring for the table; to ensure their robust growth, remove flower stalks (unless you are
growing for seed). A bonus: the large, still-closed flower buds of rhubarb can be steamed and eaten
like broccoli (they are very sour and take some getting used to!). Rhubarb contains oxalic acid, the
level of which increases as the season progresses; this has led to the tradition in Europe of ceasing to
harvest rhubarb after St. John's Eve (23 June), which also helps the plant recover for the following
year. Plants wilt in late summer and overwinter with underground buds.
All knotweed family plants develop similar fruits. Seen here are rhubarb seed stalks.
WHAT YOU'LL NEED
• three or four healthy plants
• cool, damp site
POLLINATION NOTES
Rhubarb is an outcrosser that is pollinated by wind and insects. Its perfect
flowers are inconspicuous. If you have more than one variety in your garden and you wish to produce
seed, allow only one variety to flower per year.
Rheum rhabarbarum
and
R. rhaponticum
can cross-
pollinate each other, despite being distinct species.
PROPAGATION
Varieties are easily maintained by propagating them vegetatively, which is the way
rhubarb is usually propagated. Plants require nutrient-rich soil and high humidity; they thrive in half
shade and do not like full sun. Rhubarb plants should be regenerated every eight to 12 years. Rhubarb
often thrives in a greenhouse. In autumn, plants can either be separated and replanted, or three to four
rhizomes can be taken from a two- to three-year-old mother plant. These rhizomes can be further di-
vided, such that each part has at least one bud; then the leaves are removed, and each division is pot-
