Extension Educator, Horticulture
Every family has a late bloomer, full of promise but late to show off their attributes. Every garden should have one too. Just as most flowers are fading, the late season bloomers take off and steal the show. Mums are not the only late season blooming perennials.
Fall Anemone also called Japanese Anemone is a reliable late bloomer. They may be slow to get established but take off the next season. They prefer well drained soils in a partial shaded garden The cultivar 'Margarete' has semi double flowers of striking pink with yellow centers. At three feet tall it is a nice choice for backgrounds. 'Honorine Jobert' has white single-petaled flowers that are a wonderful contrast to its dark green leaves. It's an excellent selection that has been in cultivation since 1858. 'September Charm' has single rose pink flowers.
Fall asters come in a wide range of colors and sizes. Keep in mind that not all asters bloom in fall so select plants accordingly. There are numerous species of asters and many are native to North America. Most asters prefer full sun and may need a good pinch of the stems a couple times a season to keep them from getting too lanky.
Frikart's Aster, Aster x frikartii, starts blooming in late July and continues for about eight weeks. Some notable cultivars include 'Monch' with its lavender blue flowers and 'Wonder of Staffa' with darker blue flowers. Both grow two and one half to three feet tall and show good resistance to the fungal disease powdery mildew.
The Calico Aster, Aster lateriflorus var. horizontalis is almost a shrub. The small white flowers with red centers are borne on many horizontal stems. It makes quite a show and could even be used as a low growing hedge.
New England Aster, Aster novae-angliae, has numerous cultivars. Notable ones include 'Alma Potschke', 'Hella Lacy' and 'Purple Dome.''Alma Potschke' is an excellent selection growing two to three feet tall with bright rosy pink one to two inch diameter flowers. 'Hella Lacy' was named for the wife of garden writer Allen Lacy. It can grow three to four feet tall with violet blue two-inch diameter flowers. 'Hella' needs a good pinch or staking to keep her from falling over. 'Purple Dome' is a super introduction out of Delaware. Its compact 18 to 24 inches tall habit is superior to many asters. The numerous deep blue to purple flowers cover the plants.
Russian sage, Perovskia atriplicifolia, is not a culinary sage but a beautiful three to four feet tall background plant for a sunny border. The spikes of long lasting blue flowers on silvery stems are a nice contrast with the other late bloomers in the garden. The leaves are small and silvery green with a fragrance some have joked to say smells "like the feet of Russian soldiers." Russian sage will start to bloom in mid summer but the effect will last well into fall. Full sun is a must as is a well-drained soil. 'Blue Spire' is a nice cultivar with deep blue flowers similar to 'Longin.'
Sedums have turned into one of my favorite plants. 'Autumn Joy' sedum is extremely popular with good reason. It is a durable plant growing one to two feet tall with a two feet spread. The succulent gray green leaves always look nice and highlight the starry pink flowers. Full sun is a must or it will flop. It can be cut to12 inches in June to keep it compact. 'Matrona' is a larger cultivar with maroon stems. Like the asters, sedums are real butterfly magnets.
Many of these late bloomers can be seen at the U of I Master Gardeners Idea Garden.