Strategies & tips from the pros

Welcome guests to your boat dock with a burst of color and fragrance. Whether it's one gorgeous pot or a multilevel display, you can enjoy the beauty of flowers, herbs, and vegetables on your dock all spring, summer and fall.

If you've ever tried to maintain a container garden on a dock, patio, or poolside, you know there are challenges- heat, wind, and the need for frequent watering are among them. But with creativity and ingenuity, and some advice from knowledgeable gardeners you can enjoy beautiful container gardens on your dock.

"It's important to consider how you'll keep your pots watered if you're not at the lake all week," says Sheree Paulus, longtime northern Wisconsin gardener. "Choose drought tolerant plants such as Salvia, Agastache, hybrid Origanum, Calibrachoa, Gaillardia, or Zinnia. For variety, try mixing in some perennials with the annuals. You can enjoy them in your pots all summer, and then transplant them to your garden in the fall. Check out some of the new automatic watering systems, too. Some are battery powered," says Paulus.

Ideal flower varieties for lake dock containers:

Alyssum
Coleus
Gaillardia
Geraniums
Impatiens
Lantana
Lobelia
Marigolds
Origanum (hybrid)
Nasturtiums
Nicotiana
Petunias (especially "Wave" varieties)
Roses
Rudbeckia
Salvia
Sedum
Snapdragons
Vinca
Zinnias

Ornamental grasses:

Lagurus ovatus 'Bunny Tails'
Stipa (Mexican Feather Grass)
Carex buchanii 'Red Rooster'
Pennisetum 'Rubrum' (Purple Fountain Grass)

Super Star Flowers

According to Terry Engels, Stearns County Master Gardener, "'Wave' petunias spread quickly, resist disease, need no deadheading, and are extremely hardy, blooming well into the fall. Purple Wave, and the Tidal Waves Cherry and Hot Pink have received top ratings in University of Minnesota Plant Trials. 'Profusion' zinnias are like the waves, incredibly prolific, heat and disease resistant, and do not need constant deadheading. They are consistent and trouble-free."

Vegetables and Herbs

Yes! Even vegetables and herbs can be grown on your dock. Unless you have a very shady dock, choose vegetables and herbs that can survive in full sun. Be sure to tuck in a few edible flowers, such as marigolds and nasturtiums for extra color.

Shirley Mah Kooyman from the Minnesota Landscape Arboretum advises: "Look for cultivars of vegetables that are designed specifically for patios. They will stay compact in the container. Excellent picks are patio tomatoes, bush beans, dwarf cucumbers, peppers, basil, rosemary, and thyme. But you can choose almost any plant if you have the time and patience for watering- even carrots and potatoes."

Selecting Containers

Most docks are in full sun all day. When the soil inside a container gets too hot, plant roots suffer. Wood, thick plastic or glazed ceramic planters protect roots from overheating better than clay or metal. One way to add insulation is to put one pot inside of a larger pot. Then fill the gap between with an insulating layer such as wood chips or peat moss. Keep this layer damp for extra protection and water retention.

Be sure that containers are deep enough for your plant roots and that you have ½" drainage holes in the bottom.

Filling Your Containers

If you have a huge pot you can fill the bottom third with crushed aluminum cans, a basket turned upside down, or Styrofoam peanuts. Fill your container with the Minnesota Landscape Arboretum's soil recipe, or similar mixture, and leave at least a 2" space between the top of the soil and the top of the container. You will be able to add ½" or so of mulch later to hold in moisture.

Soil Mix Recipe

Mix in the following proportions:

1/3 part purchased black soil
1/3 organic matter (such as compost, humus, or sphagnum)
1/3 lightener (such as vermiculite or perlite)

Courtesy of Minnesota Landscape Arboretum

Arrange the plants with tallest in the middle and smaller plants around the edges. Place trellises within containers as needed.

When grouping containers, use odd numbers for balance and leave plenty of room for people to walk. To prevent wind damage, attach containers to a post or railing, or even nail to the dock floor.

Strategies for Watering

Elizabeth Winn from Heidi's Lakeshore Gardens in Minnesota, suggests adding a polymer product such as "SoilMoist" to your soil. She says that it will hold water (up to 200 times its weight). "As the pot dries out the water the polymer has absorbed will be slowly released back into the soil. You can also find soil mixes that already have SoilMoist or a like product in them," Elizabeth says.

Andrew Kruger, owner of Gray Gardens in Excelsior, Minnesota, says that you can add a line to your dock when you have your lawn irrigation system installed. "This makes it easy and automatic to keep things on the dock and the shoreline watered," Kruger says.

Fertilizing

Nutrients are washed out of containers as you water so fertilize often with a balanced fertilizer. Time-released granules, such as Osmocote, are ideal if you aren't around to do frequent fertilizing. Organic gardeners recommend liquid seaweed for flowers and vegetables.

By Joni Danzl