Wednesday, March 11, 2015

Every Rain Garden Needs a Little TLC!

Rain gardens needs TLC to remain strong, beautiful and functional.

By Paige Ahlborg

With winter on the way out and spring quickly heading in, it’s time to start preparing your rain gardens for summer. What exactly does that involve? How can a rain garden be prepared for April showers so that it will display the most beautiful May flowers? Look no further; here is a basic guide to taking care of your rain garden.

Early Spring

As the snow begins to melt, it leaves a path of sediment and debris that must be removed. This list will guide you through some necessary maintenance activities:

Remove sediment from the inlet in spring.
  1. Shovel sediment from inlets, outlets and the bottom of the rain garden.
  2. Remove trash, excessive leaves, grass clippings and other debris.
  3. Clear any blockages to the inlets and outlets in order to allow proper water flow both in and out of the rain garden.
  4. Add mulch as needed to maintain a 3” depth and reduce the need for weeding and watering.
  5. Prune plants, if needed, as they become green.
  6. Leaving some stalks 15 inches or more will provide habitat for nesting pollinators, native bees and other beneficial native insects.
  7. Install new plantings in bare areas if necessary.
  8. Dispose of all accumulated material properly.

Add mulch when needed to maintain a 3" depth.

Late Spring/Summer

As the seasons change, so do the maintenance needs. These tasks can help you keep your rain garden in tip-top shape.

If weeds or invasive plants are present, pull the plants from the roots to prevent them from returning.
  • The Minnesota Department of Natural Resources website is a good resource for identifying common weeds and providing methods to control them.
  • Make a list of the native plants in your rain garden to help distinguish between desired and non-native species.
  • Ramsey-Washington Metro Watershed District’s Lake Phalen Walking Tour and Plant Guide is another resource and provides a good list of many of the native and
    non-native species that may be in your rain garden. 
Spot treat perennial weeds with an appropriate herbicide if necessary.

If there are areas of bare soil erosion, add 3” of mulch where it has been depleted. Add additional plants if necessary.

In drought conditions, water newly planted rain gardens with 1” of water weekly. Established rain gardens should not need additional water unless plants look distressed.

Continue to clear inlets and outlets of debris, sediment and trash.

If standing water is present for 48 hours or more after a rainfall, it is an indication of a malfunction that will require further study and action. Call your contractor or RWMWD to get advice on how to correct drainage issues.
Fall is a great time to add additional native plants to bare areas!


Rain gardens require maintenance before the snow falls. Here are some ways you can help make your spring cleanup a lot easier.
  • Fall is a good time to prune plants when they have gone dormant. Leaving some plants uncut provides winter cover, bird habitat and visual interest.
  • Fall is a great time for additional necessary plantings.
  • Divide plants that have become too large.
  • Remove excessive leaves from the bottom of the rain garden.
  • Continue to keep debris and sediment from inlets and outlets.

Like any garden, a rain garden requires some love and attention. Hopefully this article will help you maintain a strong, beautiful and functional rain garden.  

If you need assistance with weed and plant identification, feel free to call Ramsey-Washington Metro Watershed District at 651-792-7950. 

The Lake Phalen Walking Tour and Plant Guide is available to purchase at the District office. This field guide designed for native plant enthusiasts highlights over 170 species of native and invasive plants with numerous color photos and is a valuable tool in identifying plants.

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