Grow Jack-in-the-pulpit plants in shade gardens and/or woodland gardens. Jack-in-the-pulpit plants look good when surrounded by a mass of low-growing ground covers such as impatient Lucy (Impatiens walleriana). In fact, when Jack-in-the-pulpit plants go dormant and leave a hole in your shade garden in mid-summer, plug some impatient Lucy into the vacant spaces to fill them up again.
These wildflowers do not demand the superb drainage that many plants do, making them an option for boggy soils. The idea is to mimic the native habitat, which is damp, acidic areas of the forest rich in organic matter.
The spathe of A. consanguineum (zones 7 to 9) is purplish with light green stripes, ending in a long “tongue” that makes it look ever so much like a cobra’s head. Also with a long tongue is A. saxatile (zones 6 to 9), but in this case, the tongue is the spadix; the spathe is white. The purplish spathe of A. griffithii (zones 7 to 9) is decorated with an elaborate light-green veining pattern at the top.
The three-part compound leaf of Jack-in-the-pulpit may remind some of poison ivy (Toxicodendron radicans) at certain stages of the latter’s growth (remember, “leaflets three, let it be”). The leaf structure also resembles that of Trillium, which shares Jack-in-the-pulpit’s native habitat, as well as the nickname, “wake robin.”
Fertilizing with compost is sufficient in many cases. But use a fertilizer containing ammonium-N if your soil pH is not acidic enough.
An evenly moist soil is another must for growing Jack-in-the-pulpit.
To plant, make a 6-inch hole in the ground in fall and drop in the corm, as you would for Crocus, for example. Once the plants have come up in spring and put on some size, shovel 2 to 3 inches of mulch around them in order to conserve moisture. Slug pests like to eat this wild plant, so be sure to practice slug control, as you would for another slug magnet of the shade garden: Hosta.
Jack-in-the-pulpit needs shade, an adequate water supply, and nutrients. Once these three elements are provided, the plant is not a lot of work to grow.
The plant has some close relatives that are also in the Arisaema genus, as well as some cousins.
Jack-in-the-pulpit (Arisaema triphyllum) blooms in spring, but it is mainly the odd spathe people are drawn to. It is also valued for its red berries.