Even the most well balanced and eco-friendly garden requires a bit of pest control. I am finding that a lot of people ask about how to tackle insects that are eating their non-edible leaves of plants like root vegetables, tomatoes, beans and radishes. As these plants are grown for things other than their leaves there really isn’t any need to take any action. If pests are eating your broccoli or munching their way through your favourite ornamental like a hosta or begonia then you might need to take a bit of evasive action to keep the damage to a minimum.
I have what I think is one of the easiest and most versatile of solutions. Rhubarb .
Rhubarb doesn’t just taste delicious; amongst other things, the leaves of the plant can also provide a natural pesticide for your garden.
(Rheum rhabarbarum), is easily grown here as we have a cool climate. The plant itself originated in Asia over 5,000 years ago and was initially cultivated for its medicinal qualities.
Rhubarb has been used for centuries in traditional Chinese medicine. The dried roots of the plant are used to treat a variety of ailments, including constipation, liver and gallbladder complaints and poor blood circulation.
Rhubarb leaves are poisonous and contain oxalic acid which is highly effective in the garden. The oxalic acid in the leaves can help to control aphids, particularly on roses.
The recipe here includes soap, which I personally won’t use. It is added as a surfactant to spread out the liquid on the leaf but I don’t think it needs it. Dogs might lick the soap solution too and it won’t do them any good.
What You’ll Need
- An old pot, stirring spoon that won’t be used again for food preparation.
- A clean bucket and a spray bottle.
- Dish detergent or soap flakes – do not use laundry detergent
- Storage jar or bottle
- Trim the stalks from the leaves.
- Put the leaves into the pot.
- Bring the leaves to the boil and then reduce to a simmer for 30 minutes.
- Strain the solution into a clean bucket.
- Discard the leaves in your compost.
- Pour the strained solution into a spray bottle.
- Add 1 tspn of the detergent.
- Label as ‘POISON’.
Using Rhubarb Pesticide
Use this pesticide for controlling aphids, slugs and caterpillars that crawl on the leaf of your decorative (non edible) plants.
It might be a good idea not use this pesticide on edible crops. Though a good wash may remove the poison, I would not recommend testing it.
Remember though that this method is a last resort in the garden. Healthy plants are much less susceptible to damage from insects. So remember to feed the soil every year with well-rotted manure and compost.
Other uses for Rhubarb
Rhubarb isn’t only for pies and making a spray though. Here are some other uses for this versatile plant.
Cleaning pots and pans
Use Rhubarb to clean your pots and pans. If your pots and pans are burnt, an application of rhubarb over the afflicted area will bring back the shine in next to no time.
This is a fairly strong dye that can create a more golden hair colour for persons whose hair is blond or light brown. Simmer 3 tbsp. of rhubarb root in 2 cups of water for 15 minutes, set aside overnight, and strain. Test on a few strands to determine the effect, and then pour through the hair for a rinse. Usual disclaimers apply – I’m not responsible for the outcome!
The fibre in rhubarb is a nice additive to handmade papers.
Rhubarb needs an open, sunny site with moist, but free-draining soil and doesn’t like being waterlogged in winter. Avoid frost pockets as stems are susceptible to frost.
It can be grown from seed, but it's more common to plant dormant year old crowns between autumn and spring. Prepare the ground by some well-rotted manure, then spread out the roots and plant so the tip of the crown is just visible above the soil.
Pot-grown rhubarb can be planted at any time, but will need plenty of water during dry spells. Space plants 75-90cm (30-36in) apart, with 30cm (12in) between rows.
Rhubarb can also be planted in very large pots at least 50cm (20in) deep and wide.
Harvest the second year after planting as this will improve vigour. Remove a few stems for usuing but try to leave some to keep the plant in active growth. To remove, hold the stalk at the base and ease it out of the ground, aiming to avoid snapping it off. Although rhubarb stems remain palatable and usable through summer, it is best not to over crop the plant and end pulling by June. You can always sneak a few extra off as the season moves on.