I know that this is a little late but there are still a couple of days left in July and the advice given below applies to late summer and early fall. We need to remember that perennial flowers need attention to keep them looking their best. A flower border that comes into bloom in early summer looks amazing to begin with, but as flowers fade the plants will soon lose their pristine look without some regular TLC. This article by Kath LaLiberte which I found on the Longfield Gardens website explains what you need to do.
Part of what makes public gardens like Sissinghurst, Kew or?Longwood so impressive, is how well the plants are tended during the growing season. Keeping a?perennial garden looking good from May to September is about more than good design and smart?plant choices. It?s also about maintaining the plants?so they always look their best.
The?horticulturists?who tend?these show gardens?follow set schedules with month-by-month?instructions?for?each type of plant. There?s one?protocol for peonies and another for phlox. They know exactly when it?s time for the foxgloves to?be cut back and when the dianthus should?be sheared.
These summer maintenance tasks are just as important?at home. Without some basic deadheading and cutting back, a?perennial garden that looked fantastic in June can?look like?a mess in?August.?Now is the time to take action!
Here?s an overview of the?six basic techniques?for deadheading, pruning and shearing. You?ll need only?two hand tools: pruning shears and hedge shears.
Remove dead flowers
As flowers fade, remove them?as soon as possible. This way,?plants don?t?waste?energy trying to set seed. Biennials and short-lived perennials are the?exception (including sweet William, hollyhocks, aquilegia and biennial foxgloves). For these, producing seed is a good thing. Wait and cut them back after some or all of the seed pods have matured and released their seeds.
Remove both flower and stem
Some plants produce flower stalks that are separate from the rest of the foliage. For these, (such as daylilies, primroses, heuchera, hosta, campanula and pulmonaria), you can cut back the entire flower stalk right to the base of the plant. In most cases the plants will not rebloom, but removing the flower stalks improves the plant?s appearance and will direct more energy to the roots.
See more at Longfield Gardens