Common members of this group include gladioli, dahlias, cannas, caladiums and tuberous begonias. Plant hardy, spring-flowering bulbs from late August until the soil freezes. Daffodils should be planted in September or early October because a longer period is necessary for root development, before soil freezes and all growth stops. Fall-blooming bulbs are planted in August. As a general rule, the top of the bulb should be planted at a depth equal to 3 times the bulb's diameter.
Less harm is done by planting too deeply than is done by planting too shallowly.
Water thoroughly after planting. This helps to remove any air pockets that may remain around bulbs after planting. Also, moisture is important to begin root growth. Plant gladiolus corms at a depth of 4 to 5 inches and 6 inches apart. Although this may seem unusually deep, glads need to be anchored deeply to support the flower stalk.