News, Advice, Tips and Jobs For July 2021
In most years, July can bring the highest temperatures. This can often be accompanied by heavy rain and thunderstorms if the prevailing winds are from the west. However, this season is anything but normal with a large stationary high pressure, resulting in cool north-easterly winds We would often remind gardeners that newly planted subjects must never dry out, the big worry is that should hot dry conditions suddenly returned plants will find it very difficult to adjust and may suffer as in the case of mysterious very serious damage and even death.
In theory, the flower border should be at its best and regular dead heading is a must to prevent plants from spending their energies in producing seed. Weather permitting, July is a month in which it should be possible to enjoy eating, or simply sitting out of doors during the day and on into the long evenings.
July is also a month in which to visit some flower shows and gardens up and down the country as they begin again after Covid ‑ don't forget to take a pad and pencil to make a note of the varieties you may wish to order in time for next summer. Alternatively, modern smartphones have excellent embedded cameras to record images or to record voice memos. The following is a list of possible work for gardeners in the south Midlands; readers living elsewhere must make allowances for this and adjust their work programmes accordingly. Older copies of this fact sheet should be discarded as seasons change and so do the chemicals available for certain uses in the garden.
Covid still dominates our lives with the July Freedom date being pushed back a fortnight, this will affect Garden Centres and Nurseries, especially tearooms and restaurants
Slugs and Snails
The recent cool weather means we will see many slugs and snails devouring our choice plants. The traditional home gardener's domestic slug pellets were based on metaldehyde which is a slime activator, causing the slime glands of slugs and snails to become overactive to the point they rupture and the slug dies. There is no poison in domestic slug pellets, they contain more than 96% bran, a maximum of 3.5% metaldehyde and a fungicide. They were designed to attract slugs and snails, and I believe they are best used away from your choice plants because of this fact. A ban on these slug pellets saw several alternatives come to the market, but having tried the new safer slug pellets I can say with some certainty Traps for slugs and snails are also available along with materials which are difficult for slugs and snails to crops such as crushed rocks and copper tape. I am currently working on using Grazers Slug control which is based on a calcium extract which makes the sprayed plant material inedible to the slug or snail which results in pests starving to death. It is proving very effective for me and has seen an abundance of hedgehogs for the first time in many years.
The summer rains means that many plants and weeds seem to be growing at an alarming rate making much unwanted growth, which in many cases will be ideal for making good home-made garden compost providing you do not compost weed seeds or noxious roots such as couch grass or Mare's tail. If you cannot remove weeds, at least remove old flower heads to prevent weeds from making seeds, and do not compost these.
The heavy rains have also leached nutrients out of soils. Gardeners living on sandy soils will be familiar with the need to provide extra nutrition and this summer it will be of paramount importance to maintain sufficient nitrogen especially, as it is mobile in the soil and easily leached out so be prepared where growth turns pale green and less vigorous to use a high nitrogen feeds (Chempak and Vitax).
The excessive rains during June have put many plants under stress, with members of the leguminaceae family especially appearing to literally die on their feet. In the absence of any national advice, I would suggest that especially Wisterias seem to be suffering from three different problems, mainly caused by a massively fluctuating and often waterlogged soil moisture level. This has led to the loss of root hairs and the death of plants. The Royal Horticultural Society some years ago suggested there was a graft incompatibility problem which inhibits the movement of sap upwards in spring causing plants to die and here you sometimes see suckers trying to emerge from below the graft and these are a clear indication of graft incompatibility. Again in the lack of information available I suspect that Wisterias may also be succumbing to waterlogging diseases such as Phytophthora
Lawn Weed Control
Heavy rains have meant the weeds both in borders and the lawn are growing profusely and while this may seem a nuisance it does offer the ideal opportunity to chemically control nuisance weeds in borders and weeds in lawns. It is vital to understand that only selective hormone weedkillers should be used on lawns and where non-selective systemic weedkillers are used in borders you must keep any spray away from plants you wish to keep as even a few drops of non-selective systemic weedkiller can kill large plants.
Please follow the manufacturer’s instructions and allow around six hours in both cases for weeds to absorb the chemical before rain may occur. I recommend using a pump up sprayer with a fine mist to thoroughly coat weeds, as this gives a more effective control.
Weed control generally
Weeds will continue to germinate while the soil is moist, and it is prudent to keep the hoe moving to prevent weed seedlings germinating and becoming established. A razor sharp hoe should sever weed seedlings and this is best practised earlier in the day during sunny conditions when weeds will rapidly shrivel up, then a three-pronged cultivator may be used.
Gardeners are often accused of wasting water and the heavy rains have given us an opportunity to save water because there are bound to be much dry conditions when watering plants will be necessary, and it is far more socially acceptable to use home saved water rather than mains water especially if you are on a metered supply.
Lawn Problems and Diseases
My lawn is simply too wet being on heavy clay to put a heavy mower on, although the grass desperately needs cutting. I shall be reverting to a lightweight Rotary mower and just very lightly topping my grass on several occasions to keep it under control. I would advise gardeners to keep off lawns when they are too wet and to ensure that when knowing your lawn you collect all the grass mowings as these can lead to disease problems.
The wet conditions also make it perfect for controlling the lawn weeds. Some lawn weeds are difficult to control, often having minute hairs on the leaf surface, and from trials I have found that the latest formulation of Weedol Lawn Weedkiller gives excellent results provided you leave the lawn 5 to 7 days after applying the lawn weed killer and before mowing.
Do not compost or use the mowings immediately after using hormonal lawn weedkillers. Because of the inclement weather recently launched will require extra feeding and I strongly believe that Viano’s range of lawn feeds are some of the best materials on the market and although initially they appear more expensive in the longer term they last longer and produces a sturdier healthier and thicker sward.
The long run of wet weather has seen a proliferation of associated diseases and a slight increase in pests. Pests are easily controlled when first seen, use an appropriate pesticide. Diseases once inside a plant are exceedingly difficult to control, and fungicides are relatively ineffective. However, if you apply a fungicide to prevent diseases attacking it will be literally 100% effective and I would recommend applying fungicides on any disease prone plants in your garden before the disease appears.
Tips (To follow)
THE FLOWER GARDEN
After all the rain we had in late June there is plenty of vegetation to start a compost heap, which if properly made and managed will be ready for use in early winter.
Hanging baskets and containers are often overcrowded by July and some thinning and pinching back along with regular dead heading is recommended. Extra feeding will be necessary this year following the heavy rains.
Feed outdoor Chrysanthemums with a fertilizer that is high in potash. Make sure Chrysanthemums are properly supported, as their stems are brittle and easily broken by adverse weather conditions such as the recent high winds. Disbud early flowering varieties if they show buds. Spray regularly to control pests.
Pinks and perennial Dianthus can be increased by taking cuttings or pipings. Remove old flower stems from Pinks, water if dry and give high potash fertilizer. Continue disbudding border Carnations. Layer border carnations for new plants.
Keep Geraniums and Fuchsias well-fed and watered, particularly any standard fuchsias, which require plenty of food and water and adequate support. Fuchsias must have faded flowers removed before they form fruits, to ensure continuity of flowering.
Continue tying young dahlia stems to supports. Feed plants, which are slow to grow, with a liquid fertilizer fortnightly, taking care to keep the fertilizer away from the stem and top roots. Watch out for earwig damage and spray accordingly. After such a wet June, watch out for and control slugs and snails.
Sow biennials, including Hollyhocks, if you have not already done so. Prick out seedlings of Wallflowers, Sweet Williams etc. into an open site with good soil for them to make good growth before removal to the flowerbeds in autumn. Other hardy perennials sown earlier in the cold frame can be potted on or planted in their flowering positions if space allows.
Herbaceous beds and borders will benefit from a light dressing of general fertilizer. Hoe lightly and water in if necessary. Continue to weed carefully, but thoroughly since many weeds act as alternatives hosts to common pests and diseases such as aphids, mildew, and red spider mite. An application of general fertilizer will benefit Michaelmas daisies. Spray regularly with an appropriate fungicide to prevent powdery mildew.
Pansies and Violas can be propagated from young basal shoots after any flowers have been removed from propagation material. Sow pansy seed in cool conditions for spring flowering.
Stake Gladioli before they become too tall, taking care not to damage the new corm., tie in regularly and cut back to the first leaves any spikes that have finished flowering.
Continue cutting back and dead heading early flowering perennials. Dead head peonies by removing only the flower and seed heads. Cut Lupins and Delphiniums to ground level in mild areas to encourage a second flowering. Spray Hollyhocks with Fungus Fighter) to control hollyhock rust after removing the worst infected leaves and destroying them.
Sweet peas should be in full bloom but to maintain flowering, it is vital to prevent them from seeding by cutting off flowers as they fade. Spray Sweet Peas monthly against insect damage. A liquid feed can be given every 12‑14 days. Continue to pinch out tendrils and side shoots from cordon grown plants and layer when they reach 5 feet tall.
Continue weeding and trimming back alpines. Any carpeting plants not showing new growth should be encouraged to do so by incorporating soil and fertilizer around them. Collect seeds of Aquilegias and Primulas. Sow Primula seed as soon as it is ripe. Store other seed in a cool dry place. Aubretia cuttings can now be taken and should root out of doors if given a partially shaded, well-drained site.
Early season herbaceous that has finished flowering will benefit from being cut back, early flowering geraniums will often flower again if cut back, while it also tidies up the border and stops plants overcrowding one another.
Penstemons that have finished their first flush of flowering can be cut back to promote more flowers later in the season.
Hardy Cyclamen raised from seed can be planted into well-prepared ground, by incorporating leaf mould and/or damp peat and a dusting of bonemeal.
Spring flowering bulbs should have died down completely by now and can be lifted and stored if required. Burn any damaged bulbs. Prepare the ground for planting bulbs for spring flowers by weeding and applying a high potash fertilizer before the final cultivation. Plant autumn flowering crocus in any deep, well‑drained soil, where their vigorous foliage can be left unrestricted when it appears each spring. Nerine bowdenii can be planted in sheltered districts.
Lift and divide old clumps of bearded Iris as soon as flowering is finished. Replant immediately into rich, moist soil, if weather is particularly dry do not move until autumn. Dwarf Irises can be lifted and divided as soon as possible.
As Lupins finish their first flush of flowering to promote further flower spikes, spray against the Lupin aphid.
Deadhead roses regularly. After first flowers fade feed with a rose fertilizer to encourage the second flush, this is especially important on lighter soils and with the heavy rains leaching the nutrients out of the soil. Continue to spray against aphids, mildew, and black spot. Tie in young shoots on wall roses and climbers. Young shoots of climbing and rambling roses can be layered from now until early autumn. Make a slanting cut from a nodal bud halfway through a young branch and peg down in the soil. By next spring, new roots should have formed, ready for transplanting.
Trim hedges to maintain shape following the heavy rains that have produced excessive lush growth, keep hedges A shaped for best growth and strength. Privet and other hedges will need clipping to retain a neat shape, but do not clip too closely in very dry spells. Watch out for aphids, whitefly and other pests and spray accordingly. Newly planted hedges will need careful watering and overhead spraying.
Check tree ties and loosen, replace, or remove as necessary.
Prune early flowering shrubs such as Buddleia alternifolia, Kerria, Spiraea arguta and Deutzia by cutting out the oldest and unwanted stems to ground level if necessary. This is really the latest time to very lightly trim back deciduous Magnolias.
Outdoor Hydrangeas can be treated with a proprietary hydrangea colourant if blue flowers are required next year. Remember, only those that were originally blue flowered can be returned to blue, Pink varieties cannot be made blue.
In a dry season I would recommend topping up pools, but this year it is more a case of thinning out water lilies and oxygenating plants. Water lilies not growing may benefit from aquatic fertilizer tablets, as they are gross feeders.
Take semi‑hardwood cuttings of Azaleas, Cytisus, Spiraea, Forsythia, Escallonia, flowering currant, Weigela and Deutzia. All cuttings should have the leaf area reduced and must be shaded from bright sunlight.
Layer Chaenomeles Clematis and Jasmine if required.
All wall shrubs will need extra attention to training and tying in after the heavy rains promoted lush soft growth. Although Clematis wilt does occur, but most wilted foliage is caused by knuckled stems where excess growth causes foliage to slip on supports stopping the sap rising and stems go black. Lightly trim Clematis montana after flowering to keep the plant within bounds and to thin out overcrowded stems. It is still possible to propagate C. montana. Protect clematis against slugs and earwig damage, as both favour lush, soft growth.
Spray rhododendrons and azaleas against Japanese lacewing fly and bud blast. Safeguard these and other shallow rooting shrubs (magnolias, hydrangeas) by paying careful attention to watering and mulching.
Dead head Roses after the first flush of flowering to promote more blooms, feed with propriety Rose Fertilizer. Spray against greenfly and black spot.
Weed and mulch the heather bed.
Save seed from species around the garden alpines and herbaceous will only come true from seed if a species and there is nothing in the vicinity to hybridize with. Sow seed of Primulas immediately.
Any large leaves of the water lily that are hiding the flowers should be removed well below the surface of the water. Thin heavy oxygenating plants and regularly weed the bog garden.
In hot weather, replace lost water from the pool using a hose fitted with a spray. This will also help to aerate the pool. In very hot weather, fish and plants in shallow pools may suffer. Check the temperature of the water and shade part of the surface with a screen of hessian or opaque plastic sheeting.
Chafer grubs can be a problem this month, leave your grass longer for the next few weeks as adult Chafers always choose short thatch free top quality lawns for egg laying. My greatest worry is that if June becomes dry month 100% of chafer eggs laid will hatch, given a very wet June more than 90% will rot.
During wet warm periods this month it will often be necessary to mow the lawn twice weekly. If lawn weeds are growing actively they may be treated with a lawn hormone weed killer such as Verdone. Do not compost the next mowing and always follow the instructions fully. Lawns can be fed and moss killed without the need for raking out by using a new lawn product called Mo Bacter, which while not cheap is a very effective treatment and is widely used by turf care professionals.
Trim lawn edges regularly. Sweep up the cuttings to prevent them taking root. In dry weather water if permitted the turf twice weekly after a light aeration.
THE VEGETABLE GARDEN
Plant out Brussels sprouts, winter cabbage, Savoys and Broccoli. Use brassica collars to prevent cabbage root flies laying eggs close to host plants. Sprinkle hoof and horn meal or Vitax Q4 onto the site at the rate of 2oz. per sq.yd. (60 grams per square metre) and rake in, before planting. Do not loosen more than the top inch of soil, as brassicas require firm soil in which to grow. Watch out for the cabbage white butterfly. Eggs and caterpillars must be removed as soon as they are spotted. Enviro mesh is a very useful material that can be supported above your brassicas and prevents cabbage white butterfly and cabbage root aphid getting their host plant and laying eggs
Marrows and courgettes can be planted in prepared positions.
Pinch out tips of broad beans after flowering to deter blackly.
Plant out sweet corn, in blocks on warm soils in sheltered locations.
Sow winter hardy Swedes thinly in shallow drills, the variety Marian is resistant to mildew and clubroot diseases.
Earth up main and late cropping potatoes, watering them well in dry weather to encourage a heavier crop.
Sow turnips for a supply of tender golf ball sized roots.
Plant celery seedlings into prepared trenches and water plants in well after planting.
Tomatoes can be planted outdoors on prepared ground, staking with 4 ft. canes. Bush varieties need not be staked. Firm the soil around each plant making a slight depression, water in thoroughly. A reputable tomato feed, used as directed, will assist fruiting.
Leeks can be planted in individual holes 6‑8 inches deep. Lightly hoe between onions and work in a little fertilizer.
Make successional sowings of peas, radishes, onions, lettuce, chicory and beetroot. Sow carrots in succession for pulling young when finger thick. Sow French beans for a late crop.
Lift early potatoes towards the end of the month and prepare the ground for winter crops of brassicas etc.
Harvest herbs for drying for winter use. Make additional sowings of parsley and other annual herbs. Feed, weed and mulch established herb beds.
By the third week of the month asparagus cutting should cease. The fern like foliage should not be cut down. Mulch the asparagus bed and control any weeds at the first signs.
Cut off flowers of rhubarb. Lightly feed and mulch established clumps, water well if dry weather continues.
To encourage runner beans to set, spray with tepid water in early evening. Do not allow the soil surrounding them to dry out.
Vines growing out of doors can be stopped. Pinch out the growing points of side shoots at two leaves beyond the developing bunches of grapes.
Summer prune gooseberries, spray for aphids, caterpillars & capsid bugs.
Keep redcurrants lightly fed and mulched. Spray to control, sawfly, caterpillars, aphids and leaf spot.
Spray raspberries to control raspberry beetle grubs. Pull off or hoe up suckers outside the rows. Pelleted Poultry manure will give raspberries a boost in growth and should be well watered in after application if it does not rain within a few days.
Keep blackberries mulched to conserve moisture and swell fruit, thin the basal shoots. Spray to control raspberry beetle when flowers first open. Tie in growing shoots of blackberries and loganberries to prevent them from breaking in the wind.
Cut back summer growths on Red and white currants along with gooseberries by reducing to five leaves.
June drop of apples will occur but this is nature’s way of balancing the amount of fruit the tree things it can successfully produce. Thin as necessary dessert and culinary fruitlets. Spray apple trees to control aphids, caterpillars, capsid, scab etc., using Bug Clear for fruit and vegetables do NOT apply sprays to crops that are not specified on the label.
Keep birds and squirrels off your fruit with netting and or fruit cages.
THE INDOOR GARDEN, CONSERVATORY AND GLASSHOUSES
Keep greenhouses shaded and well ventilated. Where possible, run an greenhouse electric fan to keep the air circulating and cooler. Damp down paths and border soils frequently in hot spells to lower temperatures and reduce the risk of red spider attack.
Young Hydrangea plants that have been potted can have the growing points removed and stood outside for the summer.
Cineraria seedlings should be pricked out and successive sowings made.
Azaleas and Camellias can be stood outside in their pots in a lightly shaded position and feed with an ericaceous feed.
Sow species Clematis seeds in John Innes type compost.
Prick out Coleus seedlings. Coleus ‘Kong’ is best potted into large pots from seed trays rather than moving a small pot.
Pot on cyclamen into their final pots and move into the cold frame or grow on in a cool slightly shady spot in the greenhouse. Take care to protect them from strong light. Spray Cyclamen plants lightly overhead twice daily to deter pests and to produce healthy growth. Older established Cyclamen can have the water reduced to induce a short dormancy, the exception being plants less than two years old that do not have a sufficiently large corm to carry them through the dormant period.
Take cuttings of geraniums, fuchsias, succulents and alpines.
Arum lilies can be stood out of doors.
Achimenes will need support with short twiggy branches inserted around the pot. Keep out of full sunlight and keep water off the foliage
Sow Primula malacoides in preference to P. obconica to avoid rashes etc.
Towards the end of the month the first tomatoes will be ripening and some de‑leafing can take place below fruit that has finished swelling out.
Melons will require cross-pollination and a male flower should be removed and used to pollinate the female.
Cucumbers should be shaded from the sun and provided with a moist environment to deter the red spider mite and mildew.
Pinch out shoots on grapes two leaves beyond developing fruits and then stop at each new leaf.
Whitefly can be a nuisance in the greenhouse as they build up quickly during periods of warm weather. Take appropriate action where necessary.
Clear weeds from block paving and between slabs either using a proper tool to scrape between edges or use a fatty acid based weedkiller. Pressure washing can remove the fine sand and dirt, but this should only be replaced with proper kiln dried sand.
LOOKING GOOD THIS MONTH
Dianthus several inc. D. ‘Little Jock’
Astilbe ‘Bronze Elegance’
Iris ensata and I. germanica
Nepeta x faassenii
Paeonia lactiflora hybrids
Cistus x cyprius
Lavendula angustifolia ‘Munstead’
Viburnum plicatum ‘Maresii’
Clematis inc. C. ‘Vyvyan Pennell’, C. ‘Niobe’, C. ‘Lasurstern’, C. ‘Nelly Moser’, C. ‘Multi Blue’
Fruit and Vegetables in season
Harvest autumn sown Japanese onions by partially lifting and allowing to dry off first before storing.
Lift the first of the early potatoes after a small trial dig to establish they are mature and large enough.
Salad crops such as lettuce and radish should be harvested regularly.
Towards the end of the month, early varieties of strawberries should be ready to pick, protect from birds and slugs.
Continue to pull Rhubarb stalks until the end of the month, remove any flower buds at the first signs.
The information given in this Fact Sheet is provided in good faith. It is however of necessity general information and advice on the topic. Howard Drury will not be under any liability in respect of the provision of such advice and information and you are strongly advised to seek independent advice on any particular gardening problems or queries you may have, preferably from experts who can (when appropriate) inspect the problem before providing advice.
(C) 2021 This material has been produced by Howard Drury and must not be reproduced in part or full without the written consent of Howard Drury, Kings Heath, Birmingham, B13 0SJ.