Bulbs provide gardeners with a quick and generally inexpensive way to add color to our gardens and landscapes. There are two groups of bulbs we use throughout much of the United States;
- Fall planted bulbs that bloom from early spring to early summer (Daffodils, Tulips, Allium, Muscari, Crocus and many others)
- Spring planted bulbs that bloom beginning from mid- summer into the fall (Dahlia, Gladiolus, Crocosmia, Crinum, Canna Lilies, Calla Lilies and many others)
Many of the spring planted bulbs can be used like annual flowers and are a great way to fill in newly planted perennial beds or combine with annual bedding plants (like petunias, marigolds, lobelia and alyssum) in ground beds and potted container gardens. While other spring planted bulbs are winter cold hardy and perennial. The key to spring planted bulbs is to be sure they are compatible to your region’s summer temperatures. Some like it hot, while others are best suited to cooler climates at higher elevations.
Bulbs that are used as annuals
A number of spring planted bulbs are only perennial in zones 9-10 tolerating winter temperatures only to about 20° F. So for most of the country they are most commonly replanted each growing season as “annuals” that freeze out over the winter. For some gardeners, it is worth their while to dig (“lift”) these cold tender bulbs after hard frost and store them for replanting the next year. However you want to handle them, they provide us with magnificent flowers the same growing season that we plant them. Here is a short list of “annual” bulbs;
Dahlia (Dahlia) – native to Mexico and Central America this genus has been extensively hybridized to create a huge assortment of cultivars with many different flower shapes, colors and sizes.
Gladiola (Gladiolus) – spectacular spikes of colorful flowers that are excellent as long lasting cut flowers.
Mexican Shell Flower (Tigridia pavonia) – a heat and humidity loving wildflower from Mexico blooming in a rainbow of brilliant colors.
Freesia (Freesia) – incredibly fragrant flowers that are outstanding in container gardens.
Persian Buttercups (Ranunculus) – exquisite flowers in a wide range of brilliant colors that are best grown in areas with cooler summer temperatures or as a winter annual in hot summer regions.
Canna Lily (Canna) – heat lovers that thrive in heat and humidity but are not recommended for higher elevations where the nights are too cold.
Calla Lily (Zantedeschia) – native to South Africa, they are grown throughout the world and thrive in climates with summer heat and humidity.
NOTE: Don’t be in a rush to plant the heat loving varieties like Canna Lily, Dahlia, Calla Lily and Mexican Shell Flower. Wait until the last frost has past and the soil has begun to warm up. When it’s time to plant tomatoes, it’s time to plant these bulbs.
Cold Hardy Perennial Bulbs
Among the spring planted bulbs there are a number of cold hardy varieties that are reliably perennial and can be used in the mixed perennial flower border with great results.
Winter Hardy Gladiola (Gladiolus nanus hybrids) – these gorgeous “Glads” are cold hardy to USDA zone 5 when well mulched before the onset of winter.
European Lily (Lilium martagon) – fabulous winter hardy lilies that are long lived with large, colorful flowers that are extremely attractive to butterflies.
Pink Guernsey Lily (Nerine bowdenii) – a showy South African lily-like species that blooms in the late summer/early fall before the foliage emerges in spring.
Foxtail Lily (Eremurus stenophyllus) – A fantastic xeric flowering bulb from western Asia that blooms in early summer and thrives in the drier climates of the Intermountain West and Great Plains.
Crocosmia (Crocosmia) – a showy group of African species that bloom in mid- to late summer, these are best grown in moister climates as they dislike heat and drought.
Rain Lilies (Zephyranthes) – a large group of native bulbs that range from the Gulf States down into Central America. Rain Lilies bloom off and on all summer, especially after a good soaking rain. They are excellent naturalizing bulbs that create colorful, long lived colonies in USDA zones 7 to 11.
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