Water Arum (Calla palustris) thrives best in shallow, cold water and is commonly found growing in marshes and bogs. “Palustris,” the species name, means “of the marshes.” “Keillor,” the genus name, comes from “kallos,” the Greek word for beauty.
I. Appearance and Characteristics
Calla is a genus of flowering plant in the family Araceae, containing the single species Calla palustris (bog arum, marsh calla, wild calla, squaw claw, and water-arum).
The genus formerly also included a number of other species, which have now been transferred to the separate genus Zantedeschia. These plants from tropical Africa, however, are still often termed “calla lilies” but should not be confused with C. palustris.
It is native to cool temperate regions of the Northern Hemisphere, in central, eastern and northern Europe (France and Norway eastward), northern Asia and northern North America (Alaska, Canada, and northeastern contiguous United States).
It is a rhizomatous herbaceous perennial plant growing in bogs and ponds. The leaves are rounded to heart-shaped, 6–12 cm (2+1⁄4–4+3⁄4 in) long on a 10–20 cm (4–8 in) petiole, and 4–12 cm (1+1⁄2–4+3⁄4 in) broad. The greenish-yellow inflorescence is produced on a spadix about 4–6 cm (1+1⁄2–2+1⁄4 in) long, enclosed in a white spathe. The fruit is a cluster of red berries, each berry containing several seeds.
The plant is very poisonous when fresh due to its high oxalic acid content, but the rhizome (like that of Caladium, Colocasia, and Arum) is edible after drying, grinding, leaching and boiling.
II. How to Grow and Care
Sunlight
Water Arum flourishes in full sun conditions, where the intensity of the light promotes vigorous growth and optimal health. Although it has a tolerance for partial sun, extended periods outside its ideal light intensity can lead to suboptimal growth and potential health issues. With the capability to adapt, water Arum may exhibit certain traits like leaf orientation to maximize light absorption. It’s best planted outdoors in locations where it can bask in unfiltered sunlight for most of the day, avoiding heavily shaded areas to ensure it performs well.
Watering
Water Arum thrives in wet environments, as it is native to marshy areas and boggy grounds. This plant has a preference for high humidity levels and can tolerate standing water. Watering every week will ensure its optimal growth. Being an evergreen plant, water Arum retains its foliage throughout the year, even during periods of less rainfall, thus conserving water effectively.
Soil
Water Arum thrives in wet, marshy environments, indicating a preference for consistently moist soil.
Propagation
There are three good ways to propagate water arum plants: By germinating seeds, by dividing, and by taking cuttings.
- For the seeds, you’ll need to collect the fruit and extract the seed from the pulp.
- For cuttings, you’ll need to remove a stem with a leaf and give it the proper conditions to root.
- For division, it involves digging out a plant and splitting it into two halves.
Let’s look at the details of how to do it:
Propagate By Seed
To propagate water arum with seeds takes patience but it’s fairly low maintenance.
Water arum seeds should be picked when the fruits have dried off and turned yellowish-brown, which is later in the summer and during fall.
After you pick the seeds, they’ll need to go through a cold stratification period before they can germinate.
For cold stratification here’s what to do:
- Take a ziplock bag, tag it with the seed name and date, then fill 1/3 with sand.
- Next, add the seeds and moisten the sand, zip shut.
- Leave your seeds in your fridge for at least 90 days.
When you’ve given them time to cold-stratify, the next steps are easy enough.
- Pre-soak the seeds in water overnight.
- Fill a pot with moistened potting soil.
- Sow the seeds on the surface of the soil and press them in gently.
- Cover the pot with a plastic bag or glass jar to keep the soil moist.
- Place the pot in a warm location and keep the soil moist until the seeds germinate.
- Remove the covering once the seeds germinate and transplant the seedlings into a larger pot when they are big enough.
- Water arum can take some time to germinate, it can take up to two weeks for the first sprouts to appear.
Propagate by Division
Another great way to propagate water arum plants is to divide them.
For division, you’ll need to find a healthy wild plant first. When you do, it’s simple enough, but you must be careful not to destroy the colony.
Here’s how to do it:
- Dig up the Calla palustris plants and divide them into clumps.
- Cut through the rhizomes (underground stems) with a sharp knife.
- Make sure each clump has at least one healthy rhizome.
- Replant the clumps in fresh soil.
- Don’t put the divisions in direct sunlight for some time. They’ll be weakened and will need to strengthen in a partly shaded spot with plenty of moisture.
Propagate With Cuttings
It’s also possible to propagate water arum plants with cuttings.
You’ll just take a stem with a leaf, kind of like you would with a pothos plant.
Here’s how to do it:
- Cut a healthy stem from a Calla palustris plant with a sharp knife.
- Cut the top leaves significantly, almost down to 1/3. This will avoid moisture loss.
- Dip the cut end of the stem in rooting hormone powder, then knock off the excess with a light flick.
- Stick the stem in a closed container with a vented top, then fill it with potting soil, and water until it turns into a muck.
- Place the pot in a warm location, but away from direct sunlight.
- Keep the soil moist by watering it regularly.
- Roots will form in 2-4 weeks.
- Transplant the new plant into a larger pot when the roots are established.
When you’re ready to transplant, be careful. You should slowly acclimate the plant first since it’ll be used to a very moist environment.
Tilt the lid half off for a couple of days, then remove it for a few more days to acclimate it to the dry air.
Transplanting
Transplant water Arum during the cool, mild seasons (S1-S3) to reduce stress and ensure root establishment. It prefers wet, partially-shaded locations. TIP: Always take care when handling the delicate roots during transplanting to avoid damage. Keep it convincing, friend!