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Plant Answer Line Question

Keywords: Eruca vesicaria ssp. sativa, Rheum x hybridum, Poisonous plants

I just moved into a house with a beautiful vegetable garden with lettuce, kale, arugula and rhubarb (planted next to the lettuce). We have a 7-month old who will likely be all over the back yard in the next few months, and we have a few concerns about the rhubarb leaves, as we've heard they are poisonous.

Could rainwater roll off the rhubarb leaves and contaminate the lettuce? Could leaves left on the ground contaminate the soil? And if we touch the leaves, will the rhubarb's poisonous properties contaminate our hands?

We aren't huge rhubarb fans, so we will likely be taking them out at the end of this summer. Any tips on removing them to make sure they would not grow back?

Lastly, unrelated to rhubarb, we have some arugula that's bolted (flowered). Is there anything we can do, like cutting it back, so it won't be bitter and we can eat it? I assume we have to just replant it.


The toxic parts of rhubarb (Rheum x hybridum) are the leaves and the roots, as described by University of Illinois Extension:

"One characteristic consistent with all rhubarb is the toxicity of the leaves and roots. The rhubarb leaves contain high amounts of oxalic acid, a toxic and potentially deadly poison."

Rhubarb is a frequently grown vegetable garden plant, and is often grown in close quarters (in the same soil, with the same irrigation) with other edible plants. As long as you are careful when harvesting your lettuce not to get pieces of rhubarb leaf at the same time, you should be safe. Here is what Plant Alert: A Garden Guide for Parents by Catherine Collins (Master Craftsman, 2001) says: "The leaf blade contains high concentrations of oxalic acid [...] The stem is safe to eat, providing the leaf is removed with at least 2 inches of stalk below." (By the way, rhubarb stalks or stems, spinach, beet greens, and chard all contain lesser amounts of oxalic acid--that's what gives the chalky sensation you get on your teeth sometimes when you eat them.)

You will not be affected by the plant's leaves or roots unless you ingest them.

There aren't any special precautions you need to take in order to dig up your rhubarb, although gloves are always a good idea--you never know if your skin may be sensitive to particular plants.

About your arugula (Eruca vesicaria ssp. sativa): I usually cut the bolting stalks back, and new (and less bitter) leaves grow lower down on the plant. You could let one or two plants flower and go to seed--then you wouldn't need to buy more seed. If you still have extra seed, you can sow more (called "succession planting," described in this Organic Gardening article), in addition to cutting back the leggy stalks.

Date 2018-03-14
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May 23 2018 14:32:42