If you’ve ever seen any of the old photographs of Mark Twain smoking a pipe you’ll recognize the shape of Dutchman’s pipe flowers (Aristolochia spp.). Named for the meerschaum pipe, Dutchman’s pipe flowers grow on deciduous or evergreen woody vines in U.S. Department of Agriculture plant hardiness zones 4 through 8, depending on species. Tropical species, such as Aristolochia elegans, are not cold hardy and may be restricted to growing in USDA zones 8 to 10. This low maintenance vine blooms in early summer with showy, orchid-like flowers. Although Dutchman’s pipe seeds take from one to three months to germinate, busy moms will appreciate that while germinating, these plants are low maintenance.
The most critical requirement for seed germination is moisture – it triggers germination through absorption into the seed, a process known as imbibition. As the embryo absorbs water, it grows and expands, rupturing the seed covering. This, in turn, allows the radicle, or primary root, to emerge. Some seeds require mechanical breakdown of the outer coat to allow the absorption of water. Dutchman’s pipe seeds, on the other hand, will absorb water through the outer seed coat if soaked for 48 hours. The best way to fulfill this requirement is by filling a thermos with hot-to-the-touch tap water and dropping the seeds into it. Seal the thermos and allow the seeds to soak for 48 hours.
2. Container and Soil
Dutchman’s pipe seeds can be started in any type of container as long as there are holes in the bottom so that excess water can drain. Of critical importance is the type of soil you use to fill the pot. Since seeds and seedlings are especially attractive to various fungal pathogens that live in soil, use a soilless mixture, available at gardening centers. Fill the container with the mix and moisten thoroughly. When the mix has dried to barely moist, it’s time to plant the Dutchman’s pipe seeds.
Dutchman’s pipe seeds require light to germinate, so lay them on the surface of the mix and press down lightly on them so they make contact with the planting mix. Because they’re surface sown, the seeds will dry out quickly. To prevent this, cover the container with plastic wrap or enclose it in a sealable plastic bag. This creates a mini-greenhouse and the condensation beneath the plastic should provide the seeds with the necessary moisture.
Dutchman’s pipe seeds also require heat to germinate so place the container on a heat mat set to 70 degrees Fahrenheit. Place the heat mat, with the container on top, in an area that with ample light but no direct sunlight. Germination may take from one to three months, and the seeds won’t germinate at the same time, so have patience. When the seedlings emerge and produce their second set of leaves, gradually reduce the heat mat’s temperature over the course of a week. At the same time, start opening the plastic covering for a bit more time each day to allow the seedlings to acclimate to the dryer air outside the bag.
- The Scott Arboretum: Dutchman’s Pipe – Climbing Aristolochia
- Missouri Botanical Garden: Aristolochia Tomentosa
- North Carolina State University: Aristolochia Durior
- Floridata: Aristolochia Elegans
- Kew Royal Botanic Gardens: Environmental Conditions for Seed Germination
- Royal Holloway, University of London: Seed Germination
- National Gardening Association: Aristolochia Seed Germination
- Success with Seed: Aristolochia Littoralis - Calico flower