Thinking inside the (window) box
Dressing up your porch or patio with container plants is a great way to brighten up your house. But hanging the plants on your house takes things to a whole other level -- literally. Window boxes, which have been popular in European villages for generations, can make any house look charming. Just follow these easy steps to bring that Old World feel to your Long Island home.
Style and color
Pick a box style and color that coordinates with your house. Or buy unfinished boxes and paint them yourself. Just remember, boxes will be exposed to the elements, so they should be constructed of treated lumber, cedar or plastic, which will better withstand heat, cold and humidity than those made of untreated wood. All boxes should be lined with coconut husk mats.
Measure windows and select boxes that match their lengths. An inch or so longer or shorter is fine, but bigger differences can look awkward. Box depths should be no less than 8 inches to accommodate healthy root growth.
To avoid overflows, root rot and box damage, containers should have drainage holes in their bottoms. If they don't, you can drill them in yourself. Consider that water will drip on the ground directly below boxes, and if that's impractical because, say, that's where you park your car, then insert a perforated plastic liner on top of a coconut husk liner to slow drainage. As an alternative to perforation, use a paper hole puncher to create holes 4 inches apart in plastic liners.
Group plants according to sunlight and water requirements. Drought-tolerant plants should not be planted in boxes with water hogs, just as sun lovers shouldn't share space with shade plants.
Hang it up
For double-hung windows, allow a few inches between the bottoms of window frames and the top rims of boxes. Boxes positioned under outward-opening casement windows should be positioned a bit lower. Screw galvanized L-shaped brackets directly into wood or masonry, no more than 18 inches apart for proper support. Fasten the bottom of the box to the brackets using the included hardware.
Never fill and plant a box before installing it; its weight will cause problems. Instead, install boxes first and then fill them while standing inside the house. Use only soilless sterile potting media that contain a combination of peat moss, perlite or vermiculite, and nutrients. Gently tease the roots apart before planting in the container to stimulate root growth and hasten establishment. Or, you can opt to drop a few small potted plants directly into boxes; from ground level, they will appear to be planted in the container (if using on the first floor or on a one-story house, camouflage small pots by covering their tops with a layer of moss or mulch).
Remember, plants in containers require more frequent watering than their in-ground counterparts, especially if they're growing in full sun conditions. Check the soil moisture mornings and evenings, and aim to keep the soil consistently moist but not soggy. Deadhead spent flowers regularly to encourage more blooms and keep plants from looking messy and dropping dead material on the ground below.
Anatomy of the window box
For the most abundant-looking containers, include "thriller," "filler" and "spiller" plants:
Thrillers are upright plants that provide vertical interest. Plant one in the center of the container.
Fillers are shorter, mounding plants that should fill in the space around thrillers.
Spillers should be planted last around the outer edge of the container. Typically, these are vining or cascading plants that will drape over the sides of the box.
Here are 25 great plants for window boxes:
Purple fountain grass (Pennisetum setaceum "Rubrum")
New Zealand flax (Phormium)
Coral bells (Heuchera)
Wave Petunia (R)
Snapdragon (Antirrhinum majus)
Creeping Jenny (Lysimachia nummularia)
Sweet potato vine (Ipomoea batatas)
Nasturtium (Tropaeolum majus)
Trailing petunia (Calibrachoa)
How to choose your window plants
Consider each plant's mature height when planting, and ensure they won't grow so tall that they'll block windows.
Look for colors that contrast with the exterior wall of your house: bright or bold colors look best against a light background, while dark colors and brick show off white and pale plants best.
Window box prices vary widely, based on quality, size and style: Thirty-inch plastic boxes, for instance, start at about $5, while a high-density polyethylene box of the same size can cost $100 to $200 or more; expect to pay between $50 and several hundred dollars for similar-sized wooden boxes. Hardware costs fall into a wide range, too: A metal bracket kit can be purchased for as little as $15, whereas a single decorative corbel can cost more than $100.