Peter Cun­dall:

When your rhubarb plants start throw­ing up flower spikes all is not well in the vegie gar­den, our res­i­dent green thumb PETER CUN­DALL ad­vises

Sunday Tasmanian - Tassie Living - - TASSLE LIVING -

Top tips for grow­ing your own rhubarb

When long-es­tab­lished clumps of rhubarb start throw­ing up flower spikes, it’s usu­ally a dis­tress sig­nal. The cause may be lack of wa­ter dur­ing sum­mer, or ex­tra-poor grow­ing con­di­tions, es­pe­cially lack of sun­light.

How­ever, the most com­mon rea­son for per­sis­tent flow­er­ing and in­creas­ingly poor qual­ity or sparse rhubarb sticks is old age. Clumps need to be lifted from the ground and root masses di­vided ev­ery five or six years to keep plants grow­ing strongly.

The best time to do the job is when plants go into a form of dor­mancy in late au­tumn and win­ter.

There are sev­eral va­ri­eties of rhubarb, but they can be gen­er­ally di­vided into two main groups, those with red stems and oth­ers with green stems.

The most pop­u­lar green-stemmed va­ri­ety is Vic­to­ria and is widely grown be­cause it is vig­or­ous and pro­duc­tive. The best red-stemmed rhubarb va­ri­eties are Syd­ney Crim­son, Wandin Red and Ruby Red Dwarf, a com­pact form, ideal for grow­ing in large con­tain­ers

It’s im­pos­si­ble to make green­stemmed va­ri­eties of rhubarb turn red, al- though ex­tra-cold con­di­tions dur­ing win­ter can give some green sticks – which are al­ways fairly thick and long – a pale, red­dish base. Green va­ri­eties die back to the ground ev­ery win­ter.

Red-stemmed rhubarb tastes the same as green but looks nicer. The stems are shorter and not as thick, but are bet­ter year-round value be­cause they con­tinue pro­duc­ing light crops through win­ter.

Lift­ing an old, ex­hausted clump can take a fair amount of ef­fort. The root masses – known as ‘crowns’ can be enor­mous. It is still well worth get­ting as much crown as pos­si­ble from the ground.

I drive a sharp spade deeply around a

Red-stemmed rhubarb tastes the same as green but looks nicer ... and is bet­ter year­round value

clump, then use it to lever the en­tire root mass from the soil.

It can be a re­volt­ing sight of black, gnarled roots sur­rounded by enor­mous amounts of old, dead ma­te­ri­als. Use a hose to blast off all soil and this iso­lates the health­i­est, liv­ing di­vi­sions, eas­ily iden­ti­fied by large, green buds at the tips.

Use the spade to cut up old crowns and get rid of all use­less, half-dead ma­te­rial and old soft, partly-de­com­posed roots. An old clump can yield up to 20 or more new di­vi­sions, each with at least one healthy bud at the top.

Each of th­ese di­vi­sions will cre­ate a new, highly-pro­duc­tive, healthy clump within two years – with even a light har­vest dur­ing the first sum­mer. The se­cret of suc­cess with rhubarb is lots of old, well­rot­ted ma­nure.

I’ve had fan­tas­tic re­sults sim­ply by dig­ging in two big bags of sheep ma­nure into a square me­tre, adding half a bucket of pel­letised poul­try ma­nure and a bucket of en­riched biochar.

This make the soil ex­tremely rich and fer­tile. Af­ter all, it is im­pos­si­ble to over­feed rhubarb. Just bury two di­vi­sions on ei­ther side of the en­riched spot, leav­ing the buds just stick­ing up from the soil. Wa­ter in and leave to set­tle over win­ter.

The first shoots and un­furl­ing leaves will ap­pear in early Septem­ber and with reg­u­lar sum­mer wa­ter­ing and added welldiluted fish emul­sion ev­ery cou­ple of weeks, growth will be ex­tra­or­di­nary.

Red rhubarb clumps can be also di­vided, but it helps if older stems with large leaves are re­moved. Some­times, new­ly­planted rhubarb sends up the odd flower spike the fol­low­ing sum­mer, but this is dur­ing the ini­tial set­tling-in pe­riod.

Al­ways re­move th­ese spikes as fast as they ap­pear by giv­ing each coarse, thick stem a good twist so it snaps off cleanly at the base.

Re­mem­ber, rhubarb leaves are too toxic to eat, but if boiled in wa­ter for 20 min­utes and liq­uid strained off and col­lected, it can be mixed with a few soap flakes to make an ex­cel­lent aphid killer. And all tox­i­c­ity dis­ap­pears within hours.

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