By: Sandy Feather ©2010
Penn State Extension
Q. I have window boxes that get baked in the hot sun most of the day. Can you suggest some annual flowers that can take this southwest exposure and still look fresh?
A. You did not say how big your window boxes are, but the following plants should do well in typically purchased window boxes. These same plants will also do well in flower beds that have a hot southwest exposure. When you plant your window boxes, mix about one part compost to two parts potting soil to help hold moisture and provide some nutrients.
It also helps to mulch the soil surface after planting your window box with a thin layer of finely shredded bark or fine bark nuggets.
Ageratum - Ageratum houstonianum
Vinca - Catharanthus rosea
Pot marigold - Calendula officinalis
Cockscomb, Plumed celosia - Celosia cristata
Dianthus - Dianthus chinensis
Dahlberg Daisy - Thymophylla tenuiloba
Gaillardia - Gaillardia pulchella
Gazania - Gazania rigens
Gomphrena - Gomphrena globosa
Strawflower - Helichrysum bracteatum
Licorice Plant - Helichrysum petiolaris
Lantana - Lantana camara
Sweet Alyssum - Lobularia maritima
Bush zinnia - Melampodium paludosum
Dwarf Cupflower - Nierembergia hippomanica
Geranium - Pelargonium x hortum
Petunia - Petunia x hybrida
Portulaca - Portulaca grandiflora
Mealy Cup Sage - Salvia farinacea
Scarlet Sage - Salvia splendens
Dusty Miller - Senecio cineraria
Marigolds - Tagetes spp. & cvs.
Black-eyed Susan Vine - Thunbergia alata
Nasturtium - Tropaeolum majus (‘Alaska’ has variegated foliage)
Creeping Zinnia - Zinnia angustifolia