No one can really pinpoint when frost and snow will come. Many gardens survive just fine with no attention at all in the fall. Consider this listing and the complementary Plants to Leave Standing Until Spring, as guidelines. You will learn what works and what doesn’t, for your own garden. But it never hurts to take some time and put your garden to bed, in the fall.
- Golden Marguerite (Anthemis tinctoria) By late summer, Golden Marguerite daisies have finished blooming and are nodding off. Pruning to the crown will encourage new basal growth that helps protect and sustain them through the winter. (USDA Zones 3 - 7)
- Goldenstar (Chrysogonum virginianum) Often has problems with powdery mildew. If so, remove and destroy foliage in the fall. (USDA Zones 5 - 8)
- Ground Clematis (Clematis recta) This is a clump forming clematis that blooms late summer into fall. It produces attractive seed heads, but when hit by a frost, it’s as slimy as wet petunias. Blooms on new growth, so don’t be afraid to clean it up in the fall. (USDA Zones 3 - 7)
- Hardy Bergonia (Bergonia grandis) Frost will blacken and collapse the foliage of Bergonia. If left at the base of the plant, it can cause crown rot. Prevent this by cutting back in the fall. (USDA Zones 6 - 9) Do you notice it says Hardy but looking at the zones it isn't for us at all? I will have to check into the variety we sell to see if they are zonal for us.
- Helianthus (Perennial varieties) H. x laetiflorus, H. salicifolium...) These perennial members of the sunflower family usually finish blooming toward the end of summer and go down hill from there. Deadheading does not improve their appearance and the tall stems are guaranteed to break and flop. Cut back to ground for aesthetics. (Zones 5 - 9)
- Hollyhock Mallow (Malva alcea) See Macleaya cordata (Plume Poppy) And I do mean EVERYWHERE. (USDA Zones 4 - 8)
- Japanese Anemone (Anemone x hybrida) Japanese Anemones are favorites of certain beetles and are often defoliated by fall. If not, the foliage of Japanese Anemones turns black and very unattractive with frost. Unless your Japanese Anemones have had a very good year, it’s advised to cut them back in fall. (USDA Zones 4 - 8)
- Ligularia (Ligularia dentata) is predominantly grown for its foliage, which turns to a dark mush after frost. Feel free to cut it back. (USDA Zones 4 - 8)
- Lilyleaf Ladybell (Adenophora lilifolia) Can be cut back after flowering diminishes. Basel foliage will remain fresh until spring. (USDA Zones 4 - 8)
- Masterwort (Astrantia major) Masterwort is often deadheaded throughout the summer, to prolong the bloom time. If conditions are dry, the foliage will begin to yellow and it can be sheared to the crown. Allow the new growth to remain through the winter. If no yellowing occurs, leave the plants for spring cleaning. (USDA Zones 4 - 7)
- Meadow Rue (Thalictrum aquilegiifolium) Performance wise, it doesn’t really matter when you cut back Meadow Rue. But since it’s done flowering for the season, pruning in the fall is one less thing to do in the spring. However, some varieties will self-seed. If that’s desirable, let it go until spring. (USDA zones 5 - 8)
- Mountain Bluet (Centaurea montana) Mountain bluets tend to become black and unsightly with the first frost and can be cut back in the fall. However, if you sheared them back in late summer and only basal growth is present, you can allow that to remain. (USDA Zones 3 - 8) Another name for this is perennial Bachelor Buttons Hope this helps another day I will give you the rest of the list. Till next time, this is Becky Litterer from Becky's Greenhouse, Dougherty Iowa