What to do in the garden in July

 The garden is in full swing with many gardens at their peak in July, along with the veg plot full of produce. Its a lovely time of year in the garden.   

At their best in July are Delphiniums,  Agapanthuslavender, various ClematisAchillea,  Dahlias Nepeta Thalictrum late flowering Peonies, Day Lily, Roses,  Sweet peasHoneysuckle;  it's all blooming, and the garden is full of beautiful scents.

One of the main gardening tasks in July is dead heading the various flowering plants. For most plants this just means snipping off the spent flowers, but for some plants it's a little different. Also, it is important not to dead head any plant which you want to display berries or hips later in the year, such as Rosa rugosa or Honeysuckle.

Keep on deadheading

Deadheading

If you just have a few minutes to spare, the time will be well spent dead heading. To keep summer plants and bedding at its best and to prolong flowering, it is essential to dead head. The purpose of dead heading is to encourage more flowering. Once the plant has flowered and set seed,  so it can reproduce, plants are often reluctant to flower again, or continuously. Dead heading, which is cutting off the spent flower head, forces the plant back into the cycle to produce flower and seeds again. Some plants, such as in the image left,  common name ice plants (Mesembryanthemum) need a lot of attention and constant dead heading.

With some plants they need so much needs dead heading, it can be easier to take the shears to the top growth and very often a second growth and flush will follow, as with Alchemilla mollis, common name Lady's Mantle and hardy geraniums (not Pelargoniums) Chives and Nepeta can also be cut back.

How to dead head roses

In July Roses are looking at their best and it is just as important to keep dead heading to get as many blooms as possible.  There is a specific way to dead head Roses which is that it is best to snap off, not prune away, the spent flower and it will break just below the flower bud.  An equally well-respected way to dead head roses is to prune back from the dead flower to the next leaf joint. Peter Beale is a well known rose grower and his video advice on dead heading roses is very useful.

How to dead head Delphinium, foxgloves and Verbascum

When the flower spike has faded and gone over, cut it back by removing the flower head only, as in just the flower spike,  not the whole stem and where there are side shoots surround the flower head , these may produce a second flush. 

What are rose suckers

Rose-and-sucker-foilage-text

Suckers can be a problem with Roses and arise from how Roses are cultivated, which is a form of grafting. A sucker is an unwanted growth from the rootstock and it is often vigorous growth and can over-take the Rose. The image left is Rosa "Little Pet" showing the true rose foliage, darker and more compact foliage at the bottom of the image. The top of the image shows the sucker foliage with a little rose foliage in the bottom left of the image below the sucker. The sucker foliage is a lighter in colour, the leaves are similar but a different shape and it is much more vigorous. If you have a rose bush which is showing one or two shoots which are growing much more strongly examine it to check it is not a sucker. 

Suckers really do sucker the life out of the rose and need to be removed. Using thick gloves go to the base of the plant where the sucker is exiting the soil, scrape away the soil and if the sucker is not too established it should be possible to pull it away below the rose graft at the base. It is best not to prune it away if you can help it, but if the sucker is well established, as was this one, it maybe impossible to pull away the sucker without damaging the plant in which case you will have to prune it away. 

Cut back early perennials

Early flowering perennials can begin to look a bit tired by July and their foliage is becoming tatty and brown. If these plants are cut back now, many will produce fresh green growth to liven up the border and sometimes even a second flush of flowers. Good candidates for this treatment are Oriental poppies, Alchemilla mollis, hardy Geraniums, Nepeta. Cut back close to the ground, feed and wait a couple of weeks.  It can look a bit bare when you first to this and if you don't like the sight of too much earth, cut back just before you go on holiday. More about cutting back Perennials It seems a bit drastic to razor over Alchemilla mollis, but in a couple of weeks time you will be rewarded with a fresh green mound of new leaves.

Summer Prune Wisteria

July or early August is the time to prune Wisteria for the second time in the year. Twice yearly pruning is essential to keep Wisteria flowering each year. If you grow Wisteria, prune now otherwise you may jeopardise next year's flowers. To maintain flowering Wisteria must be pruned in July/August and Jan/February, which makes it time consuming to grow as Wisteria can get very large requiring ladders to get to the upper reaches of the plant for pruning.

Prune back the whippy summer growth to contain the plant. Wisteria is vigorous and needs harsh treatment. Cut the whippy tendrils which have grown over summer back to about 15cm (6") long. There is a popular Sunday Gardener video viewed over 200,000 times on how to grow and prune Wisteria.  If the main stems are growing out of their allotted space, cut back now to restrict the plant.  This is a good time to feed Wisteria and Tomato feed is suitable, if your plant looks in need. I have never fed wisteria, and if it is growing well do not feed as you risk upsetting the balance between green leafy growth and flowers.  Only feed if you have a problem.

Visit the Wisteria page where information about pruning Wisteria and how to ensure it flowers year on year.

Tips on growing Sweet peas

Lovely sweet peas

Sweet peas are lovely but at this time of year to keep them at their best Sweet peas need regular attention.

To keep Sweet Peas flowering it is essential to pick, pick and pick the flowers. Don't worry that by doing this you will remove all the flowers; picking all the flowers makes the plant produce more and more flowers. If any flowers have gone over and left a seed head behind, remove it. By doing this you will keep the plant flowering and in a good summer I have picked the last of the Sweet Peas in October.

Sweet Peas look best in vases if they have straight stems and to get those lovely straight stems you need to remove the thin tendrils which the plant produces which they use to cling onto the support. If the tendrils are left on the plant the tendrils twine around other parts of the sweet pea plant stopping its growth, and pulling bits of the plants down causing it to become tangled. The plant becomes a tangled mess, and this prevents the flowers having those lovely straight stems which look so lovely when displayed as cut flowers.

For more about growing sweet peas. 

Take Clematis cuttings

If you want to try your hand at propagating Clematis July is a good time.  Cut off a length of recent growth, maybe 500 cms, and then snip it into bits each about 8-10cms with a pair of leaves. It is important to have the node (knobbly bit on the cutting ) in the middle of the stem that you are going to use. Discard the very top of the cutting, which will be too soft. Fill a pot with seed compost, make few holes and tuck cutting in with hormone rooting powder if you have it, but not essential. The trick, and why it works sometimes and not others, is the cutting must not dry out, but not too wet or it will damp/rot off. Try placing in propagator or put a poly bag over the pot and seal tightly with elastic band or string and ensure place warm but out of sunlight. Check weekly for signs of growth, and to ensure it's not dried out when water gently.

July in the Veg plot

By July, beans, lettuce, rocket, courgette, spring onions, strawberries and many early crops are ready for harvesting. At last it's time to start eating and tasting. It is also the holiday season, if you are going away, check out holiday tips for ideas on how to look after your plants whilst away. 

When to Harvest Potatoes

Harvest Potatoes

When growing potatoes,  depending on the summer weather,  they do need a water  during dry spells, especially if you are growing potatoes in containers. Water is key to a good crop and Potatoes in tubs easily dry out. In addition, if you have time,  it helps to get a good crop to "earth up" the potatoes as it allows more potatoes to form as the season goes on.  To do this, as the potato grows and more stem appears above ground,  you need to add more soil to the container, or mound up the soil in the plot, so that more of the stalk is covered.  For more about growing potatoes, follow the link and check out the video about earthing up and blight.

Depending on the weather, salad potatoes and earlies will be ready to harvest in July.

How to tell when potatoes are ready to harvest?  First, have they flowered? Potatoes are not ready to harvest until after flowering and then check if they are ready by gently scraping away the earth and see what you find; if the Potatoes are too small or too few,  cover up and try again in a couple of weeks.

Growing Parsley from Seed

Parsley can be tricky to germinate and July is a good month to try. Sow in a line in the veg plot, ( lines help you to tell what is germinating seed which is growing in a line because that is how you have sown it, and what is germinating weeds, which don't grow in straight lines) and give Parsley some time as it's slow to germinate. Parsley will survive low temperatures later in the season and is an ideal herb for potting up and bringing indoors later in the year. Supermarket herbs are expensive and growing your own herbs is easy and cheap.

Peas and Beans

Runner beans in flower

Keep picking Peas and Beans whilst they are young, and if you have a glut, freeze. All the bean family freeze easily. Blanch them in boiling water for 2 mins, plunge into iced bowl to cool, pat dry and freeze. Keep picking all the peas and beans to encourage the plant to keep flowering and setting more seed.

Broad beans are very prone to black fly and to prevent this keep pinching out the tips to stop the black fly setting on the new growth, which is the bit they really like. This also stops off the plant growth so the plants energies go to flower and bean production, not more growth.

If the whole stem of beans  has been picked clean of beans, cut it down near the base and you can often encourage more growth and a second crop.

How to Make new Strawberry plants

In July you can raise new strawberry from the runners. Just place a pot of compost near the plant, peg the runner into the pot, water well and leave for a few weeks until well rooted. Cut off excess runners to conserve the plant's energies. This is helpful as strawberry plants are short lived, 3 years or so and need regular replacements and this is a way to have new plants for free.

Tips on Growing Tomatoes

Tom tie too tight

Whether you are growing tomatoes under glass or outdoors, the plants will continue to need a lot of attention. The essentials step with tomatoes, to get the flavour and texture right, is to feed and water regularly. By July the tomato plants will be growing vigorously and its important to divert the plant's energy into fruits, not foliage.

Tomatoes are a vigorous plant and you need to keep them in check. Nip out all side shoots, and thin down, which means cut off leaves to add light for when the flowers turn to fruit and to restrict growth. Once the plant has set 3/4 flower trusses, stop off  the growing point and keep pinching it out to stop the plant growing. 

As the plant grows, it will need plenty of support and tie it in using soft ties. Be careful not to tie too tightly as the image on the left shows. The tie may be loose when first placed on the plant but as the stem grows, it can become tight which will damage the stem and wound the plant.  For more about growing tomatoes follow the link which gives detailed advice about watering, feeding, nipping the side shoots and other tips for growing tomatoes successfully. Regular watering is essential for a good crop of tomatoes the plants should not be allowed to dry out.

Pinching out the side shoots is important because the plant is vigorous, if the side shoots are not taken off the plant will throw out more and more branches, growing thicker and what you want is less leaves and more flowers. The short video shows how to identify and remove the side shoots also a handy guide "Success with Tomatoes" by the Sunday Gardener. 

For successive crops you need to sow and plant successively, and in July there is still time to sow directly into the plot the last sowing of  beans and peas.  Salad crops  especially the fast growing ones, (such as rocket and cut and come again lettuce) continue to sow through July, August, and September, depending on the weather.

Last updated 29.06.2020