A well tended perennial garden will keep your gardens looking their absolute best in the heat of the season

Our perennial gardens can turn to a mess quickly in late July or August if we ignore basic maintenance and clean up. Some of our fussier plants may require specific maintenance at specific times, and I like to keep a little reminder list of those chores so they don’t get out of control. But I also keep a reminder list of which plants to just leave alone all season!

This natural progression from stunning and colorful to a midsummer mess is simply due to the seasonal maturing of our plants. Most of them begin working toward their mission of self preservation and propagation. Energy all goes toward protective dormancy or producing fruit and seed and the foliage gets weak or simply begins to die off. The weakening plants become more susceptible to disease and insect damage.

There are several simple maintenance procedures that can help keep the gardens looking fresh and vigorous. Understanding the results of these actions can help you determine just what to do when and why.

Remove fading and dead blooms

As flowers fade and die the plant begins sending energy to setting fruit and seed rather than keeping the foliage fresh and robust. As the foliage weakens it not only becomes unsightly but is more susceptible to disease and insect damage. So remove fading foliage throughout the flowering season but especially after the blooming has peaked. Biennials and short lived perennials that need to self seed of course must be allowed to complete the seed production and drop seeds for next year. Once they have dropped seed they can be cut back.

Plants that produce blooms from a flower stalk may not re-bloom, but the stalk can be cut back all the way to the base of the plant. Some of the long blooming perennials such as phlox and delphinium may fade back from the top of the flower stem down. These can be cut back to unopened buds and cut all the way back once all buds have opened and died. Deadheading these type of plants will not encourage a re-bloom, but removing the spent blooms will allow the plant to direct energy toward strong and healthy roots and foliage.

Plants that produce blooms at the tips of the foliage stems, such as hydrangea and peonies, should be pruned to a set of leaves. New blooms will not be produced but pruning can restore a more appealing shape as well as remove unattractive dead blooms.

Some of our perennials can grow to be quite bushy and leggy. They may need fairly aggressive pruning and can be sheared by as much as half. Many will produce more blooms if sheared when the summer flush of flowers tapers off. Then fertilize to encourage more blooming and fresh growth. Catmint, Coreopsis, and Cranesbill in particular respond well to shearing.

Fall blooming perennials such as asters and mums should be pinched back frequently until July to produce full bushy growth and loads and loads of blooms.

If you also grow annuals, they of course need frequent deadheading for continuous blooms. Or cut long stems of flowers and foliage frequently to keep a vase full of fresh blooms indoors all summer.

Refresh foliage

Any perennial, no matter when it blooms, will benefit from the removal of worn out foliage. Remove any damaged, dead, yellowing or diseased leaves as well as any wayward growth that detracts from the shape. The plant will not waste energy trying to heal and repair.

Staking

Tall plants, weak stems, heavy blooms, all can cause plants to flop over. Ideally these should be staked early in the season as it gets more difficult to install staking for some plants once they are full. Even plants such as Monkshood, with strong and sturdy stems, can be bent over and ruined in high winds or strong rainstorms.

Water

Be sure to keep up watering, especially when there is little rain or summer heat is drying the soil and stressing the plants. Remember that your plants are at their peak size in mid summer so they will be drawing more water now than previously. Soak the soil deeply when you do water, those roots have grown and gone deep so you want to make sure the soil is moistened for the entire root mass. If possible use a soaker or drip hose rather than overhead sprinkling. Give special attention to watering your newest plants.

Feed

Plants need nutrition all season to grow, to produce blooms, to support full foliage and even to prepare for dormancy. Be careful not to overfeed, but rather regularly feed moderately. Lightly work compost into the soil surface or top dress around shallow rooted plants. Or use a slow release fertilizer in spring and midseason. When using commercial fertilizers, look for a high middle number, which is the phosphorous. Phosphorous aids your plants with building strong roots and producing blooms. Always follow package directions.

Mulch

Add an inch or more of fresh mulch throughout your gardens. Bare soil or even thinning mulch can erode and wash out in heavy downpours. Additional mulch will help the soil retain moisture and will help keep roots cooler in the summer heat. Deep mulch will also help keep weeds tamped down. You may also be amazed at how lovely even a waning garden can look with fresh mulch throughout.

Weeding

The dreaded chore of weeding, but so satisfying once done! Try to get weeding done soon after a soaking rain so the soil gives up the weed root more easily. Weeds that have grown large will also have very large and extensive root systems. Tease these roots out carefully to avoid disturbing roots of surrounding perennials.

Inspect

Mid summer is prime time for diseases and insect damage to appear. Frequent inspection will help prevent devastation. Remove damaged foliage and do NOT put it in your compost. Damaging insects can be frequently hosed off the plant or picked off and destroyed.

Replace and add plants

Mid summer is a good time to evaluate failing plants and either replace them or move them to a preferred spot. Perhaps a plant that is not getting enough sun, or too much, will be happier if you move it. Perhaps some plants did not grow as large as anticipated, resulting in gaps in the planting beds. You could pop in a few annuals for the season or add new perennials right away. Be sure to give them plenty of water to help them establish in the heat of the season. One advantage to planting mid to late season is garden centers start reducing price to clear their inventory.

Remember that you don’t need to do it all in one day! Try to enjoy your time in the garden rather than viewing it as a lot of work. Get a little done in the mornings, then relax in the garden with a lemonade in the afternoon!