Late-Summer Garden Tasks for a Happy Garden

Late-Summer Garden Tasks for a Happy Garden

Sometimes this time of year is referred to as the “dog days of summer”; however, I do not think of it in these terms. Yes, it is hot, many garden flowers are flagging, and there are garden tasks to do, but August is also a month when there is much for us to enjoy in the garden. As I sit on my deck this August morning, I am surrounded by colorful pots of salvia, begonias, lobelia, heliotrope, abutilon, fuchsias, and even a Doris Day floribunda rose bush. But, to enjoy the late-summer garden, it needs daily care.

Groom Tired Flowers

Flagging petunias will appreciate a mid- to late-summer haircut to keep them pretty into fall.

One of my early morning tasks is to remove old flowers and perform some general grooming to keep all my garden plants looking as good as possible. I carry a pair of sharp pruners and snip off any out-of-line branches, poor-looking foliage, or dying flowers. It takes little effort and keeps the garden looking its best. (For more detail, read Teri Keith’s recent article about pruning and deadheading garden perennials and annuals in midsummer.)

Cut Flowers for Bouquets

Cut bouquets of your favorite, long-lasting cut flowers in the garden.

Dahlias are just coming into their prime blooming season and should continue to flower until about the middle of October.  Yesterday, as I was walking my dog, a neighbor was cutting dahlias and gave me a beautiful bouquet. On hot days, dahlia foliage and flowers can quickly wilt in the summer sun, and a top dressing of Black Gold Garden Compost Blend can help alleviate this issue by helping to retain moisture. Cut dahlia flowers early in the day when they look their best and keep them picked to prolong their blooming season. (Click here to read our recent garden article detailing Jessie Keith’s favorite summer cut flowers.)

Feed Container Gardens

Now is the time to fertilize and give containers extra water.

By the time August arrives, many plants in containers that have grown throughout the summer will have root systems that have begun to fill the container. Once roots fill a container, they will begin to circle the wall of the pot resulting in a pot-bound planting. This root mass will quickly become dry, and the plants will wilt from lack of water. I have found that some containers may need watering twice a day if it is hot and especially if there are drying winds. Don’t expect rain to supply the needed moisture as the foliage can be so thick that the water does not penetrate the soil. Water each container at the base of the plants until the water runs out of the bottom of the pot into the saucer or reservoir. August is also a good time to give plants in containers fresh all-purpose fertilizer because many of the original nutrients have leached out.

Prepare the Vegetable Garden for Fall

Late summer is the time to plant cool-season crops, like lettuce.

Some early-season vegetables may be on the decline. Remove them to make space for a fall vegetable garden. Add fresh amendments before planting fall vegetables. Black Gold Natural & Organic Ultra Outdoor Planting Mix is a great vegetable garden amendment that is OMRI Listed for organic gardening and contains mycorrhizae to encourage better growth, naturally.

It depends on the specific area you live in, but here in Oregon’s Willamette Valley, we plant peas can good herbs for the fall garden as well as beets, carrots, chard, lettuce, and kale as well as other brassicas. Now is the perfect time to purchase seeds and get your fall vegetables growing.

“Edit” Your Garden for Fall

Iris and daylilies can be divided in late summer as you “edit” your garden.

August is a good month to think about some garden editing. In my own garden, I occasionally plant plants in the wrong place, or perhaps they have grown larger than I had expected. When moving them to new locations, I make sure to remember where spring bulbs are planted, or I move the bulbs as needed. I also consider the surrounding area and how it might have changed in terms of light and wind. As trees and shrubs grow or are pruned, they may be casting shade on plants that need the sun or providing more sun to an area that was once shady.

If your garden has bearded or Siberian iris, late August is an ideal time to divide them. Often, beds of bearded iris decline in bloom because they are too crowded, while clumps of Siberian iris can quickly become too dense. Diving both about every three years will ensure that they bloom beautifully each spring and don’t overgrow an area.

Give Roses a Boost

Now’s the time to prune off damaged branches, old blooms, and feed your roses for the fall.

Keep roses picked and cut the stems long on hybrid-tea types for the vase. New growth will appear, and the new flowers of fall will be more at eye level where their scent can be best enjoyed. Fertilize roses one last time before spring.

In these troubling times, our gardens, whether large or small, can offer us a hiatus from some of the negative forces around us.  Even a small area on a deck, balcony, or patio can give us some respite from the world in which we live. Enjoy your plants, and realize that they don’t know what is going on around them. Give them water and nurture them, and they will provide you with much pleasure.

When is the Best Time to Prune Buddleia in California?

“When is the best time to prune Buddleia?” Question from Angie of Fort Bragg, California

Answer: In your coastal Mendocino County location, I would cut your butterfly bush (Buddleia spp.) back when your cool, wet winter hits. Butterfly bush does not look its best when chillier temperatures hit, even though it remains evergreen to semi-evergreen where you live, so prune it back by 1-2 feet once it stops blooming well, and its leaves start to flag. This will also make your garden look tidier during the chillier months and result in a more compact shrub. And, because it blooms on new wood and grows post-pruning quickly, you can feel confident that the shrub and flower buds will not be harmed.

Another factor is that butterfly bush self-sows prolifically and is considered invasive in your area. Pruning it back and removing its old buds before seedset will also reduce the chance of spread in your garden and beyond.

I hope that this information helps!

Happy gardening,

Jessie Keith

Black Gold Horticulturist


DIY Garden Project: How to Prune and Deadhead Perennials

To keep perennial garden flowers looking nice in your beds, keep the old foliage, flowering stems, and seedheads but back. Cutting back old perennial parts keeps plants looking clean and attractive and helps rebloomers flower more. Here’s how!

Click here for a Step-by-Step pdf.

Smart Summer Pruning and Deadheading

Removing the old, spent flowers from perennials, like this coneflower, will keep the plants flowering and looking great for longer. (photo by Jessie Keith)

Summer is not the time of year when most gardeners prune, but there are some definite advantages to summer pruning. It is easier to identify damaged or ill branches when a tree is in full leaf. When a tree is in full leaf it is also easier to identify branches that can be removed to provide better air circulation. A reminder: if you are going to do summer pruning on fruit trees, do it after the fruit has set.

Summer Pruning

Deadheading modern rose varieties will encourage new roses to appear. (photo by Jessie Keith)

For those gardeners that have espaliered fruit trees, constant summer pruning is a necessity. With the tree sending out new branches, it is important not to let these grow too long but to keep them trimmed so the tree is kept properly trained and maintained. For gardeners that would like to be able to grow their own fruit trees, but have limited space, growing espaliered trees is an excellent option to consider.

There is confusion among gardeners as to when and how to prune hydrangeas. Some hydrangeas bloom on 2nd-year wood, so if a plant is severely pruned one season, it may take a full year for it to come into bloom again. There are other Hydrangeas, ‘Limelight’ is a good example, that bloom on new growth. This means it can be pruned at almost any time and still produce flowers. Check with your local garden center to learn the best time to prune your hydrangeas and still get flowers.

Check with gardening neighbors and garden experts to get additional tips on pruning. Find a neighbor that likes to garden and soak up some information. One of the best things about gardening is that most gardeners are very friendly, helpful, and like to share information.

growth buds that reside on either side of it.


When removing the summer seed heads from Rhododendron, be sure not to remove the new

“Deadheading” means is removing the old flower stems to make way for new. The word is used frequently with regard to rhododendrons and azaleas and refers to snapping or cutting off the area where the old flower was attached to the stem. With most rhododendrons and azaleas, this area is usually very visible which makes removal easy. Often, this is done for visual purposes because dried up flowers are not very attractive. Removing the flowers is also a way to prevent the plant from forming seed. When a plant forms seeds, it takes away nourishment that could be used for new growth. Be careful when removing the seed head because new growth buds reside on either side of it and should not be removed. These new buds will produce the new growth for the summer and this growth will then develop flower buds for next years’ bloom.DRoses are another plant that responds well to having the flower stems removed after the flowers are gone. This will encourage the plant to produce new stems and new flowers. Stem removal can also be seen as a way to perform some selective summer pruning and will help ‘open’ the bush up to allow for good air circulation. Just be sure to sanitize your pruners between plants to protect against any potential spread of disease.

Winter is not pruning season for all plants, even though most gardeners traditionally prune in the cold season. Sometimes what is traditional, is simply that, ‘traditional’ and may have no actual factual basis.

For espaliered fruit trees, constant summer pruning is a necessity. (Image by Jessie Keith)

Spring Rhododendron and Rose Care

Once Rhododendron flowers have died, remove them from the base to stop seed development.

Spring is a good time for some general maintenance pruning on some trees and shrubs.  If your rhododendrons have not been deadheaded, it should be done as soon as possible.  I have to smile to myself when I use the word ‘deadhead’ as it is commonly used in garden lingo and many of us think everyone understands the meaning but that is not always the case.  I once had someone ask me, very seriously, what exactly did I mean when I said ‘deadhead’!  And when I paused briefly to consider the question, I could understand their uncertainty.

Beneath each rhododendron bloom lies two leaf buds. Be sure not to cut these off when deadheading your rhododendron.

Deadheading Rhododendrons

To put the word in the context, deadheading rhododendrons means to remove all of the unattractive dead or dying flower clusters.  If left on the plant, they will begin to produce seed, which takes energy the plant could be using for growth and vigor.  Look closely at the flower cluster, and it will have a stem that attaches to the branch.  The flower cluster should be cut or snapped off just above the junction where it meets the branch.  Remove the stem carefully because at the base there will be one, or several, new leaf buds forming that will emerge as the present year’s new growth. Be sure not to cut these.

Rhododendrons can also be pruned hard if they have gotten too tall.  Pruning after blooming is ideal.  If pruning is delayed, the buds for next year’s flowers will develop, and pruning hard will result in few or no flowers the following year.  If this has happened, and the plant needs to be pruned for height purposes, hard pruning should not harm the plant but don’t expect flowers.

Summer Rose Care

Cut the stems of hybrid teas lower than normal to regulate shrub size while encouraging more flowering

Hybrid tea roses often grow to six feet or more in one season, which is an unwelcome height in many gardens.  It is easy to continually prune roses throughout the season, as flower stems are cut for arrangements, but this may not be enough.  So, try cutting flowers and pruning at once. For example, if the desired rose height is four feet, go down the stem to the desired height when cutting a flower.  Roses are quite forgiving, and soon new flower buds will follow.  The advantage of pruning continuously throughout the season is that there will always be some bloom on some of the plants.  We are growing roses for their flowers and everything we can do to encourage flower production and keep the bush the size we want is the ideal goal to strive for.

Pruning Trees & Shrubs in Summer

Sometimes I think it is easier to do spring pruning on deciduous trees and shrubs because it is easier to see what branches need to be removed.  Once they have lost their leaves, it can be difficult to remember which branches were well placed and which were not.  Home gardeners can also prune and shape spring-flowering shrubs, such as lilac, Korean spice viburnum, and daphne, once flowering has ceased. With shrubs like these, it is essential to prune just after they flower to ensure you don’t remove next year’s flowers.

Prune lilacs just after they have bloomed. (Image by Jessie Keith)

As we head into summer, we have been having some record high temperatures here in the Pacific Northwest with little rain.  Many plants are suffering from these temperatures, but some techniques can help. It is not too late to add a mulch of Black Gold Waterhold Cocoblend Potting Soil, to help preserve soil moisture.  Plants in pots will benefit from this as much as those in the ground.  Try it. You will be surprised at the water-holding properties of this mix, and I think your plants will thank you.