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).
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
