Is there a list of annuals native to the Americas (preferably North America) that would be suitable for a Toronto (Scarborough) garden. Not a big garden. I believe that portulaca, petunias, and zinnia are examples.
Thank you for contacting the Toronto Master Gardeners with your inquiry.
Annual flowers complete their life cycle in one growing season, during which time they grow, flower, and produce seed. Annuals are easy to grow, produce instant colour, and most important, they bloom for most of the growing season. The main disadvantage of annuals is that you must sow them from seed or set out transplants every year. Just as we have seen an increase in the use of native trees, shrubs and perennials in the garden the trend has continued to the use of native annuals.To successfully establish native annuals in your landscape, you need to match them to the appropriate growing conditions.
Not knowing your soil conditions or your exposure (full sun, part shade, full shade) it is difficult to give you a specific list. You might find some of the plants on the following list of interest
ANNUALS FOR SPECIAL ENVIRONMENTS
Ageratum Morning glory, Amaranth Nasturtium, Balsam Nicotiana, Begonia Petunia, Celosia Salvia, Coleus Verbena, Impatiens Vinca, Marigold Zinnia
Ageratum Larkspur, Castor Bean Marigold, Celosia Morning glory, Cleome Nicotiana, Cornflower Nierembergia, Cosmos Phlox drummondii, Dusty Miller Pinks, Four o’clock Portulaca, Gaillardia Salvia, Gazania Scabiosa, Geranium Shasta daisy, Globe Amaranth Sunflower, Verbena, Helichrysum Zinnia, Heliotrope
EXTREMELY HEAT-RESISTANT ANNUALS
Four o’clock Sunflower, Morning Glory Zinnia
ANNUALS FOR PARTIAL SHADE
Alyssum Lobelia, Aster Myosotis, Nasturtium, Begonia Nicotiana, Browallia Pansy, Calendula Petunia, Coleus Snapdragon, Cornflower Torenia, Wallflower
ANNUALS THAT TOLERATE HEAT,DROUGHT, AND SANDY SOILS
Alyssum Phlox, Cleome Portulaca, Daisy Salvia, Gaillardia Sunflower, Gloriosa Verbena, Marigold Zinnia
The Toronto Master Gardeners have a gardening Guide on Drought Tolerant Annuals