Cool Water Plants for Hot Days

By Joe Summers

(This article was first published in The Gateway Gardener July 2006 issue)

A photo of a water gardenThe hot days of summer hit and we gardeners must take it easy with an ice cold drink and enjoy all the cool plants that we have chosen for our landscape.  The water garden is a nice retreat from the heat, anyway, but when we have such neat plants to enjoy, it only makes it all the more worth the effort.  I have picked just three plants I feel will add the touch of being cool on hot days.

One of the most popular pond plants ever, has to be papyrus (Cyperus papyrus).  Papyrus

a photo of Papyrus King Tut

Papyrus 'King Tut'

has been used in the garden since before the Pharaohs ruled Egypt.  Yes, this is the plant that the Egyptians used to create paper.  Papyrus has large green balls or puffs atop sturdy stems.  The puffs resemble a frozen-in-time firework display at Fair St. Louis, some reaching a full 12 inches across.  Papyrus will grow about 5 feet tall, and a clump can be 2 feet in diameter.  Although this is a tropical plant in our region the summer display is well worth it.  When night frost is forecast in the fall, then simply move your plant into a sunny window indoors.  Water the papyrus as a houseplant during the winter months.  In the summer papyrus can be placed in as much as 12 inches of water in full sun to medium shade.  For best growth fertilize about once per month.

A second cool plant that you may want to try in your water feature is the rain lily, (Zephyranthes candida).  The white rain lily is hardy in St. Louis and is a pure delight.  This well-behaved pond plant emerges from a bulb with grassy foliage in a dense clump.  The deep green leaves reach about 10 to 12 inches tall and highlight the white flowers.  Each bloom is about 2 inches across and resembles a crocus flower.  You can grow white rain lilies in full sun to part shade and from moist soil to under three inches of water.

The third and final cool plant for hot days is water mint, (Mentha aquatica).  Water mint has a running habit and will reach about 18 inches tall and wide.  Part shade to full sun is best, and you can grow mint in as little one inch of water to as much as four inches.  There are two readily available forms of water mint, flat-leaf and curly-leaf, both of which are hardy in St. Louis.  Each will bloom in late summer with lavender clusters.  Butterflies love water mint blooms and you will love the foliage.  The strong mint scent is evident if you crush a leaf.  The leaves can be used in teas and jellies.

Perhaps the best way to have cool plants on hot days is to sit in the shade and drink a Mojito prepared with your very own water mint.  After you have a Mojito or two you won’t even notice how hot it is.

Joe Summers has worked in the pond and water garden industry for many years, and recently has opened a new retail store called Chalily Ponds and Water Gardens at 14430 Manchester Rd. in Ballwin.