When to Plant Flowering Bulbs for Summer

  • Difficulty Rating: Beginner
Summer Flowering Bulbs

Adding summer delights to your garden is easy to do with unique bulbs.

Spring blooming bulbs, especially daffodils, are satisfying and easy to grow but there are also a host of bulbs that bloom in summer, including ornamental onions (Alliums), lilies and crinums.  

Like their spring blooming relatives, these bulbs offer a lot and demand little in return. Choosing the right bulb for the right place will ensure you have success.  

Summer Flowering Bulbs Alliums

Hardy lilies come in a range of colors and some bear fragrant flowers too. ‘Casa Blanca’ lilies offer the perfect complement for perennials such as Phlox paniculata ‘David,’ a white flowering garden phlox (also mildew resistant). Their sweet scented flowers, combined with the fact that they bloom in mid to late summer, make these elegant white flowering lilies irresistible. 

While they reach up to 5’ high, these hardy bulbs are narrow and can be tucked in next to shrubs and other perennials. They are happiest if you plant them in a rich, well-drained soil in a spot that gets full sun (six hours or more per day). If you like more colorful types, the list of lilies to try is long with varieties that bloom anywhere from early to late summer.  

Summer Flowering Bulbs Phlox and Casa Blanca-Lillies

The best time to plant lilies in Zone 7 and warmer is when you receive them, provided the ground is not frozen and the soil is well drained.

Adequate water is essential to help the new bulbs take root. The Fiskars Easy-Pour Watering Can is lightweight and has dual handles which makes it easy to use when spot watering new plantings of bulbs or perennials.   

Even though they bloom in summer, Alliums (ornamental onions) should be planted in the fall when they are dormant, before the ground freezes.  

Plant them at a depth that is three times the width of the bulb and site them in full sun in a well-drained soil. If they are actively growing in containers and you plant them during the growing season, dig a hole that is equal to the size of the container they are growing in. 

Allium christophii (the large flowers are stunning) and Allium giganteum , are both ideal for tucking into the perennial garden where they add a touch of drama in summer.

One allium that grows happily in more southern climates is Allium ‘Millenium’ a hybrid that produces rosy-purple flower heads in late summer. Combine it with lambs ear plants.  This small bulb is perfect for edging or the front of a perennial planting.  

Summer Flowering Bulbs Planting Alliums

Another summer delight is Lycoris squamigera, (hardy from Zone 5 to 9) also known as naked ladies or surprise lilies in full bloom. The Surprise Lily blooms appear almost like magic, lavender-pink amaryllis-like flowers on 3’ tall bare stems. Their foliage appears in the spring and dies back before they bloom.

Summer Flowering Bulbs Lycoris-squamigera

Plant these bulbs in the fall, five to six inches deep and six to eight inches apart. They will grow in part shade or full sun.  

Later in the summer, in August or even September, red spider lily, Lycoris radiata (Zone 6 to 9) is hard to miss with its bright red-orange flowers. Combine it with ferns like Southern Shield fern, Thelypteris kunthii, or other shade loving perennials like hellebores and hostas.  

Plant red spider lilies in the fall, with ¼” of the neck exposed. Plant them in part shade or full sun.  

Summer Flowering Bulbs Crinum-x-powellii-'Album'

If you garden in a region that is Zone 7 or warmer, and have room for them, Crinum lilies, also called milk and wine lilies, make a dramatic statement with their bold evergreen foliage, and deliciously fragrant trumpet-shaped blossoms.  Some bloom in summer and others continue well into fall. As they mature, clumps can easily measure 3’ to 5’ across with flowers appearing on stalks 2’ to 3’ tall. These adaptable bulbs tolerate a wide range of soil types but resent being moved, so make sure you site them where they will have room to grow.

When you plant them, dig a hole that is as wide and deep as the container they are growing in