Hardy Marginal Aquatic Plants
Hardy marginal plants include many water plants up to USDA Zone 5 or 6 (depending how protected your pond area may be). These hardy plants will survive our hard winters. Although they will go dormant soon after the first hard frost, these plants will come back in the spring.
DEPTH: 1” to 6” below the surface of the water
WINTER CARE: In most cases you will want to cut back foliage to approx 1” above planting media level and place at the bottom of the pond for the winter. Some of the actual ‘marginal plants’ can actually be left right where they are planted. In fact, as a water gardener, we plant many of these plants directly into the stream beds and pond edges. Cattails are at least one exception to this rule. You will want to leave them standing tall throughout the winter and cut back in the Spring when new growth appears. If you use Standard cattail rather than the graceful or dwarf varieties, Be sure to keep them contained in strong pots so as to protect the liner of your pond from their aggressive roots.
SPRING CARE: Do not assume plants are dead if there is no growth. Some plants may not come out of dormancy until late Spring, others like the Marsh Marigold are very early bloomers. Bring any of the plants that you submerged for the winter back up to the surface and place them at their normal 1” to 6” below the surface.
MAINTENANCE: Most marginal plants may need to be divided annually to prevent overcrowding. Fertilize as you divide your plants and anytime you notice yellowing foliage. You may choose to do a monthly maintenance on your plants, which includes trimming dead foliage and spent flowers. Be careful not to over fertilize, excess fertilizer can increase your chances of excess algae bloom.