Meadowsweet is a perennial in USDA Plant Hardiness Zones 3 through 7. It thrives in soil that is moist but not soggy. While the soil requirement is the limiting factor, the light requirement can range from full sun to partial shade.
When it comes to propagating this perennial, this plant can be started from division and seed. The trick of dividing this plant is the fact that each section needs to have at least one rhizome. Seeds, on the other hand, need a little extra work to get them to germinate.
Planting meadowsweet seeds begins with timing. If you have availability to meadowsweet, harvest the seeds once they become ripe in the fall. At this point, you can save them or plant them back into the garden but if you area does not get cold, you will need to mimic this condition.
To do this, place the seeds in a breathable container such as a paper envelope and store in the fridge for three months. After this time period has passed, you can directly seed or start them indoors.
While direct seeding is easier, it is harder to keep tabs on the moisture level. In doing so, I would recommend that you start your meadowsweet seeds inside.
To start your meadowsweet seeds indoors, begin with the cold exposure discussed above. After the seeds have chilled for three months, remove them from the cold. Prepare your four inch deep container by cleaning and sterilizing it in water with a capful of bleach. Once cleaned, rinse in clear water and sit out to dry. Next, fill with an all purpose potting soil. Sprinkle to the seed on top of the soil surface. At this point, lightly cover the seeds with perlite and mist the soil surface with water. The perlite will absorb the water and keep your seeds moist. Place the planted container in a sunny location.
Now, keep the soil evenly moist. How do you know if you need to water the container? All you need to do is to insert your finger into the soil. If you pull your finger out and the soil does not feel moist then you need to water. If this is the case, do not simply pour water on top of the soil. Mist the soil with water until the seeds begin to germinate, which can take up to three months.
Once the seeds have germinated, keep them indoors until two weeks prior to your local frost free date. At that time, harden off the plants and then plant in a sunny location.