Growing Rhubarb

Latest Update 8th August 2016.

Rhubarb
  • The photo shows a 15 months old rhubarb plant in late spring  It was propagated by division from a 4th generation plant, latest in a line of plants going back 25 years.  
  • It grows well in my soil and has been pest free until 2 years ago when Harlequin Beatles took a liking to it, and I am now having trouble getting rid of them. 
  • The stems of rhubarb are edible but the leaves are poisonous to humans and domestic animals (but definitely not to harlequin bugs).  Care should be taken when handling the leaves.
  • The poisonous oxalic acid in rhubarb leaves is neutralised in the compost heap and any part of the plant can be recycled safely. 
  • Historically rhubarb was used medicinally as a herb (as a laxative).  In more recent times it has been grown as a vegetable and used like a fruit in pies and jams.
  • I stew rhubarb stalks with apples sweetened with sugar to make a pie filler, and make jams accompanied by blackberries or ginger.  I usually maintain a few jars of each of them after sterilizing them in a pressure cooker.
  • Rhubarb grows all year round in Melbourne, although it slows down in winter and will lose a few leaves if we get a frost (becoming rare).
Details.
  • Family Group:                                            Polygonaceae.
  • Garden bed type:                                       Drip line irrigated organic bed.
  • Recommended soil pH:                              5.5 - 7.0.  
  • Minimum Sun per Day:                               5 hours.
  • Plant Spacings (centres):                           1000mm.  
  • Weeks to Harvest:                                     52 after planting , then continuously. 
  • Climate:                                                    Warm Temperate.  
  • Geographic Hemisphere:                            Southern.

Growing Conditions.
  • Rhubarb grows best in full sun, but it will tolerate partial shade.
  • They grow continuously in our warm temperate climate, but growth slows a lot in winter.
  • They prefer well drained soil, but the soil needs to be kept moist.
  • They withstand hot dry weather so long as they have plenty of water.
  • They benefit from a thick layer of mulch in summer. 
Soil Preparation.
  • In Spring, clear a space for the rhubarb by removing old mulch, dead leaves and unwanted organic material.  Choose a place where it has not been grown for several years. 
  • Apply a top dressing of home made compost at a rate of 60 litres /M2 and cultivate gently to 100mm depth.
Growing Instructions. 
  • You can lift and divide a mature rhubarb plant to make more plants.  Its best to do this in winter using plants more than 5 years old.  
  • Look for the new shoots or crowns and cut the old plant into pieces with a spade.  Each piece must contain a crown with plenty of roots attached.
  • Divide the plant in winter and plant the pieces in your prepared soil.  Bury the roots leaving the crowns exposed and water them in well.
  • The whole plant can be moved at any age, but should be relocated every 3 years to well prepared new soil for maximum vigour.  
  • They live a long time (up to 20 years), but are heavy feeders and to optimise quality and output, you need to keep them well fed with plenty of compost applied as a top dressing each spring.
  • Once the plants are established cover the soil with fresh mulch and apply a foliar spray of aerated compost tea every 4 weeks. 
  • Water frequently when its hot and dry in summer.
Harvesting and Storage
  • Rhubarb can be harvested at any time once the plant is well established.
  • Begin using the stalks as soon as the plant is large enough to spare some.
  • Only harvest the plants stalks, as the leaves and roots are poisonous.  However, these leaves and roots can be safely disposed of in your compost heap. 
  • Take stalks from the perimeter of the plant and break them off from the base with a sharp sideways tug.
  • Trim off the leaves and after washing chop them into 25mm long pieces and stew them in a small amount of water with plenty of sugar sprinkled on them.  As they heat up, they release water from their cells, so not much added water is needed.
  • We usually mix the rhubarb with apples 50% each and after stewing, bottle them for future use. 
Organic Pest Control. 
  • Harlequin Beetles.
    • I hunt them early in the morning (summer) when they are still slow.  When I see one of them there are usually 3 or 4 more hidden in the foliage close by.  I place a bucket under the bugs and tap the leaves they are feeding on.
    • Their escape strategy is to drop to the ground out of reach in dense foliage, but I catch them in my bucket and summarily execute them.
    • That wonderful mentor on all things organic in the garden Peter Cundall former presenter of the ABC's Gardening Australia program sprays a strong detergent solution onto the bugs.  It gets into their breathing tubes and suffocates them.