When should the Emergent and Submergent plants be planted during the year into a Storm Water Pond?
Thank you for contacting Toronto Master Gardeners with your enquiry about planting times for emergenet and submergent plants for Stormwater Retention Ponds.
Stormwater management ponds are the most common end-of-pipe stormwater management facility, and are reliable in operation, over a range of different storm events. The City currently maintains about 85 retention and detention ponds for the purposes of stormwater management. Retention ponds, also commonly called wet ponds refer to facilities that maintain a permanent pool.
In 2015, the City of Toronto developed Landscape Design Guidelines for Storm Water Management Ponds. This document is available on line:
Page 15 discusses zone 2 which covers submergent and emergent vegetation that should be used in the shallow water area zone. Planting times are as follows:
If bare root stock including root tubers and rhizomes is used: Spring: from frost free ground, generally early-April to mid-May, must be before bud break. • Fall: from approximately 2 to 3 weeks after leaf drop to midOctober. • If container grown stock is used, plant from mid-April to midOctober. Seeding Emergents can be introduced using an approved seedbank material or an appropriate stormwater management pond native seed mix. Native grass and herb seed mixtures should be sown in the early spring before mid-April or late in the fall; mid-October to mid-November.
Appendix A, lists Acceptable Plant Species for Stormwater retention ponds.