Dainty, delicate forget-me-nots (Myosotis spp.) exist in a wide variety of types and colors, including the common forget-me-not (Myosotis sylvatica) and the true forget-me-not (Myosotis scorpioides). All varieties grow well in pots, where their sometimes aggressive growth can be more easily controlled. Potted forget-me-nots need relatively little care once established, but they must be grown under the right conditions to encourage flowering.
Climate and HardinessForget-me-nots grow best in U.S. Department of Agriculture plant hardiness zones 3 to 8, although hardiness varies between species and cultivars. The common forget-me-not grows in USDA zones 3 to 8, with cultivars such as ‘Victoria Blue’ (Myosotis sylvatica‘Victoria Blue’) thriving in USDA zones 3 to 9. True forget-me-nots are slightly less cold-tolerant and perform best in USDA zones 5 to 9.
Regardless of species or cultivar, all forget-me-nots share the need for similar growing conditions. Sun exposure is a key factor to growing forget-me-nots, especially when cultivating them in pots. Midday shade suffices in cooler climates, although part shade all day is best in warmer climates with hot summers. Forget-me-nots handle full sun better when grown in very moist or wet soil.
Choosing the right pot and soil also plays a major role in growing potted forget-me-nots. Both common and true forget-me-nots reach a similar mature height of 6 to 12 inches, although the former spreads 6 to 8 inches while the latter spreads 8 to 12 inches. A12- to 18-inch pot with multiple drainage holes around the base will provide the right amount of space and the correct drainage for a single forget-me-not plant, or plant two plants in a 24- to 36-inch pot.
Forget-me-nots need moderate to poor soil fertility to perform well. Mix 2 parts potting soil, 1 part compost and 1 part coarse sand to improve the drainage and nutrient content of the soil. Fill to within 2-inches of the top of the pot and don't tamp down soil too much. Rich soil encourages legginess and poor blooming, so avoid potting mixes with added fertilizer.