News, Tips, Advice and jobs for June 2023
By Howard Drury
We have seen April and May bring some of the best weather for sunshine, however the hot, sunny days are often followed by very cool nights, bringing its own challenges for gardeners. The high pressure centred to the west of the UK seems to be airy fixed, possibly drifting slightly eastwards in the first week of June. This may bring in slightly milder air from the south, possibly preceded by thunderstorms, especially for the south-west of the UK.
The following is a list of possible work for gardeners in the south Midlands, bearing in mind that April was exceptionally warm compared with that very cold April 2021 with frosts recorded here in the Midlands for 28 days out of the month; readers living elsewhere must make allowances for this and adjust their work programme accordingly. I will update this as June rushes upon us.
News
The Flower Shows are back, starting at Harrogate, Malvern and Chelsea, with Gardener's World Live due to open in June at the NEC. I will be attending Gardener's World Live to see the Peter Seabrook garden, something Peter designed himself prior to his tragic death in February this year.
Advice
The best advice must be to garden with the weather, it is difficult to keep plants alive in any situation when temperatures day after day were in the upper twenties, however the start of June with mixed showery weather makes it ideal for planting out and seed sowing, but this also makes ideal conditions for weed seeds to germinate. It is best to hoe regularly, almost before the weeds appear.
Tips
Lily beetle is one of those RHS top 10 problems that makes its appearance this month, and it can be treated by applying Grazers Lily Beetle Control evenly all over the foliage including the underside of all leaves and is most effective as a preventative rather than a control. It is organic and its mode of action is to deter the beetle from feeding while enhancing the growth of the lilies and related subjects. Recently, Monty Don recommended hand-picking and then crushing the bright red beetles. Another idea is to lay some large sheets of newspaper under your lilies and leave them for a few hours before returning to shake the plant, displacing the beetles to the newspaper where they can be screwed up and incinerated in a safe place. For more information, I am in the process of preparing a specific fact sheet on The Red Lily Beetle, so please do call back again shortly. You can carry out a search using the words Red Lily Beetle to find more information in the meanwhile.
Chafer grub is perhaps the number one problem, and I am revising my fact sheet offering information about the different species of chafer grub and possible means of control using both organic and chemical methods. June is the critical month in the life cycle of this serious pest as eggs are laid at the beginning of the month and should do dry weather continue virtually all the eggs will hatch and turn into grubs which is part of their life cycle will eat the roots of your lawn.
My best advice is to leave the lawn longer this month, as the female chafer's egg laying device cannot reach through layers of thatch or long grass. This is also essential advice during periods of drought. Towards the end of the month, the soil should be warm enough to order online nematodes, which will only be successful if the soil is sufficiently moist and the temperature above 15 °C. The one silly thing here is that if the very showery weather continues, or you soaked the lawn sufficiently without using new the nematodes, theoretically the eggs would all rot so should we pray for a wet June or play on the safe side and apply the nematodes, I'd leave the choice to you as it is a difficult decision seeing what damage can be done to lawn not just by the chafer grubs but by badgers and foxes searching for chafer grubs as a source of food.
Another serious problem is occurring on species of conifer is where aphids and spider mite are causing the death of considerable areas of foliage but unfortunately will never green up again. This is a very big issue, and I'm currently carrying out investigations and looking at possible controls, and hopefully next month I will be able to offer more information on this subject. It is probably worse this year due to us having a mild winter and early warm spring, leading to considerable early soft growth and an abundance of the pest overwintering.
The wet winter followed by the dry long warm spring have led to the death of many plants including my large Victoria plum tree which stood in water logged ground for several weeks and then dried out completely, stresses like this will cause plant losses, however I will leave the tree in place until next spring to see if it comes into leave and grows away next spring.
As some of you have remarked wisteria is around the country seemed to be in trouble and I suspect the wet April has caused the loss of root hairs on many plants, I'm currently in contact with various organizations trying to find out more information on the subject, and will bring you that just as soon as possible. There is also the possibilities that the cold in April has simply delayed their burst into growth, although on a recent Ashwood trip we saw several that were clearly totally dead! Will investigate and make comment later.
Weeds are often a major problem in June and while Roundup can be used on weeds it will also kill any other plant it comes into contact with, so it must be used with care amongst other plants such as herbaceous. Several people of bought in examples of a prostrate weed with a yellow flower resembling clover with a black base to the petal, and this is almost certainly the black medic and is difficult to control because of hairs on the leaf. I would recommend Verdone hormone lawn weed killer applied early in the morning via a fine mist of a good quality pressurized sprayer, you are unlikely to get rid of this issue in just one application because there will be countless years of seed laid in the soil below your lawn. It is a common concern on sandy acidic soils such as found around Ashwood nurseries, Kinver and certain areas of Stourbridge.
The Flower Garden
Watering is of prime importance at this time of year, even more so due to the very dry spring, especially with newly planted subjects. Special attention must be paid to all types of containers, hanging baskets, tubs etc. as these can dry out very quickly in hot spells. Mulch herbaceous borders and beds (after rain when the soil is still damp) to conserve moisture and keep down the weeds. Most years it is essential to soak the ground thoroughly; if only the surface soil is moistened it will encourage the plant to make surface roots that are more liable to suffer from drought. Use mulches and mulch sheets to conserve moisture after rain or watering where possible. Target water to plant root areas only using drip watering equipment.
Regular hoeing (even if you cannot see weeds) and hand weeding will keep other areas weed free. Apply weedkillers to paths and paved areas before the weeds get too big during dry periods of dry weather, taking care not to splash weedkiller onto any cultivated areas. Do not allow weedkiller to seep into ponds, where it may kill the fish and plants.
Dead heading early herbaceous and the first flush of roses is an important task this month and throughout the summer if the flowering period of many plants is to be prolonged. The dead heads should be removed with secateurs and the stem cut back to a leaf or leaves.
After such a wet winter, keep a look-out for slugs and treat accordingly. At the first signs of aphid damage on plants, spray with a suitable insecticide to eradicate them. Hellebores seem to be covered in the Hellebore aphid already and can spread viruses. Take care not to spray when plants or trees are in full blossom, otherwise the bees, which pollinate these plants, will also be killed.
Herbaceous plants will benefit from a light feed of liquid manure or a general fertilizer, alternatively apply pelleted chicken manure. Early flowering herbaceous plants can be cut back after flowering. Delphiniums and other tall plants will need staking against wind damage if this has not already been carried out.
Any bedding out should be completed as soon as possible, watering in thoroughly if the weather continues to be very dry. Watering of any plants is best done in late evening at this time of the year.
Hardy Primulas that have finished flowering such as P. pulverulenta, P. denticulata and P. japonica can be lifted and divided before replanting in semi‑shaded moist positions. Where seed is required, remember to collect it just as the seed coats turn brown and rattles in the pod, sow immediately for the best results.
Feed and mulch Clematis, tying in new growths where necessary to give even cover, this is an ideal month to plant Clematis. The early flowering C. montana, C. alpina and C. macropetala types can be pruned as necessary together with C. armandii. (see Fact Sheet on Clematis)
June is the ideal month to plant out large well-grown hardy Fuchsia plants from pots, planting holes should be 4‑6" deeper than the pot. The hole is then filled only to the top of the root ball. The depression left is then gradually filled during the summer months until the soil around the plant stem is level with the surrounding areas. This ensures the root ball is deep enough to avoid normal penetrating frosts. Existing plantings should be fed and mulched, new growths tied in where necessary or pinched out where bushier plants are required. Control aphids and capsid bugs with systemic insecticides.
Hydrangeas are best planted this month, it allows longer for the plant to establish, but it does mean you have to be prepared to water them as dictated by the weather and the soil moisture. Nurseries such as Ashwood usually have good selection as the new crop becomes available.
Spray roses with a combined insecticide/fungicide and foliar feed such as Rose Clear. Side buds can be removed from roses if quality blooms are required. Remove any suckers as they appear. Tie in new growths on both rambler and climbing roses.
Check Gladioli for thrips and spray as necessary. Give plants a good soaking in dry weather, ideally in the evenings or early mornings.
As weather permits and the danger of frost has passed, plant out hardened off well-grown Dahlias. Pinch out growing points at 15-20cms (6‑8 ins.), water and feed as necessary.
Cut back stems of Bearded Iris after flowering and top dress poor soils with general fertilizer. Iris can be divided and replanted, always leaving the rhizomes showing above soil level to allow the sun to bake the roots.
Spring flowering bulbs whose foliage has turned yellow can be lifted if necessary and stored in trays in a dry, well-ventilated shed. Where bulbs are to be left in situ, do not remove foliage until it has turned yellow and died down completely. Plant Anemone de Caen corms for autumn and winter flowering out of doors in mild districts.
Continue to pinch out the side shoots and tendrils on cordon grown Sweet Peas. Mist the whole plant in dry spells and do not allow to dry out. Deadhead regularly. Any plant that turns yellow or discoloured should be lifted and burnt.
Sowings of winter flowering Pansies can be made in seed trays and placed in cool places in greenhouses or other sheltered places. Hardy perennials, such as Lupins, Hollyhocks, and Delphiniums etc. can be sown out of doors. Sow Wallflowers, Sweet William, and Forget-me-not.
Trim dead heads from Aubrietia and Saxifrage to prevent seeding. Clip any other plants to keep rock garden tidy. Annuals can be planted to fill any gaps that are evident. Lift and divide Saxifrages, Sedums and Aubrietias if necessary.
Thin hardy annuals as required and provide twiggy supports if necessary lightly feed plants as flower buds develop, water with fine spray if dry weather prevails. Make later sowings to provide extra colour where possible.
Keep Camellias well-fed and mulch with peat, lime‑free bark or leaf-mould, prune lightly into shape if necessary. Plant Camellias in leaf mould enriched lime‑free soil (use Carr’s Soil Improver or Ericaceous compost to improve your soil where established plants will be shaded from early morning sun in the winter and from the dangers of a hot summer sun, however avoid heavy shade.
Keep tree fern trunks moist by regularly spraying the trunk and fronds.
Water and feed Chrysanthemums keep plants netted or tied into stakes, pinch out tips of plants to promote lateral growths. Set out plants and control aphids, leaf miners and slugs.
Heathers of all types should be kept mulched to conserve moisture and encourage new root formation; trim plants that have finished flowering, older plants can be layered or dropped in order to produce new plants.
Magnolias should be only lightly pruned with secateurs after flowering to reduce overcrowding and maintain a balanced shape. Container grown plants can be planted out into rich lime free soil that is moisture retentive, but free draining. Choose well-lit or slightly shaded sites that are protected from strong winds. Remember that M. grandiflora and other evergreen types are best planted against south/west facing walls. Mulch established plants with lime‑free materials and avoid cultivations in the area.
Cuttings of Pinks can be taken and inserted in sandy soil or in pots. Stake border Carnations if not already carried out and watch for pests and diseases, taking the necessary action at the first sign of trouble. Lightly feed plants.
Sow Polyanthus and plant out resulting seedlings in shady nursery beds.
Prune Diervillas, Philadelphus, Deutzias and Escallonia after flowering to encourage new growth. To prevent Broom from seeding, cut flowering shoots back hard when flowering ceases.
Layer shoots of Clematis and Chaenomeles in pots of sandy peat, severing a year later. Take half ripe cuttings from Magnolia and Viburnum. Cuttings of Hydrangeas can also be taken.
Evergreen hedges can be lightly trimmed early in the month and sprayed with an insecticide to prevent conifer spider or conifer aphid damage.
Hanging baskets can be put out early in the month and should be sited according to the selection of plants chosen for the basket. The use of water absorbing granules will reduce the amount of watering necessary. Hanging pots have become very popular over recent years and most have the advantage of an inbuilt saucer and are ideal for the smaller garden or patio.
Towards the end of the month Daffodils that have lost most of their foliage may be lifted, and the bulbs ripened and stored ready for replanting as soon as possible, as they deteriorate if left out of the ground any length of time.
Cut down old flowered spikes of Delphiniums and Lupins as soon as flowers fade, plant out young seedlings, control mildew, caterpillars, aphids and slugs.
Take cuttings from non-flowering shoots of Pinks, put cuttings around the edge of a 10 cm pot and after watering in place n a shady cold frame.
Lift and divide suitable alpines, potting sections and keeping in shaded cold frame or cool greenhouse, cuttings can be taken from non-flowering shoots of many kinds and rooted as small softwood cuttings in a closed case or propagator
Divide pot and garden grown Auriculas, carefully separating the offsets and replanting or repotting them into auricula compost after dipping in an insecticide to control vine weevil and mealy bug, keep plants in a cool shady place afterwards, water carefully.
Box blight is a major problem, target water to root areas avoiding splashing the foliage, don’t clip to short, and you may feed with a special box feed or a seaweed-based feed. Fungus Fighter contains chemicals said to control Box Blight, it's on the label, so it must work! By law!
The Lawn
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.
The Fruit Garden
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 thinks 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.
Conservatories, Greenhouses and other Protected Situations
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.
Wildlife and Nature
General Maintenance
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
Alpines
Dianthus several Inc. D. ‘Little Jock’
Bulbs
Alliums
Annuals
Nigella
Herbaceous
Alchemilla mollis
Achillea ‘Fanal’
Astilbe ‘Bronze Elegance’
Iris ensata and I. germanica
Nepeta x faassenii
Paeonia lactiflora hybrids
Shrubs - deciduous
Buddleja globosa
Cistus x cyprius
Lavendula angustifolia ‘Munstead’
Tamarix tetandra
Weigelia
Viburnum plicatum ‘Maresii’
Shrubs - evergreen
Climbers
Clematis inc. C. ‘Vyvyan Pennell’, C. ‘Niobe’, C. ‘Lasurstern’, C. ‘Nelly Moser’, C. ‘Multi Blue’
Lonicera heckrottii
Trees
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.
© 2022 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.
JHD/18.02.2022
