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Expert Garden Advice for July 2019 Jun 30

June has ended on a high note hardly living up at the last minute to its accolade of "flaming June" after several weeks of dull often chilly weather for the time of year. The last couple of days have seen record temperatures achieved although thankfully not as hot as in Europe.

Although the pressure is mostly off to get on with lots of jobs in the garden – there’s still plenty to do. The approach to High Summer is the time to really enjoy the garden – but watering, feeding deadheading and checking for pests and diseases are all a priority in July.

Once you’ve done all those you can sit down, relax and enjoy yourself ! As I observed one well known garden speaker say recently if you are able to practice year round gardening this takes the pressure off doing those jobs that still need doing & you can sit watch & contemplate in your garden in peace. If you have not managed to achieve everything you wanted in time for high summer never mind this year just relax anyway ! 

July Garden Tips were written for us exclusively by a nationally know garden expert and whilst we do not think that many readers will have the time to follow them  to the letter a broad range approach to the tips will ensure that you get the best out of the growing part of your garden this summer.


General

It’s not necessary to regularly water all the plants in your garden, but all recently planted plants – especially bedding – will appreciate a good soak every seven to 14 days during dry weather to aid rapid establishment.When watering established plants give a thorough soaking weekly; watering little and often encourages surface rooting and makes the plants more susceptible to drought and drying out.
Plants growing in containers are likely to need watering daily or every other day, depending on the weather.

If you have a lot of plants in containers, in the greenhouse or large areas of the garden that need watering, consider installing a micro-drip watering system. If you use a watering computer too, it will even water your plants while you’re away.

Feeding is also important. Either use a liquid feed in the water or add a long-lasting, once a year controlled-release fertiliser to the soil or compost. Flowering plants benefit from a high potash feed.

Pot on plants showing signs of being potbound. Carefully tip out plants that are looking unhappy to see if they are potbound or if they are suffering from some other problem.

Use all your weeds (apart from the roots of perennials), lawn clippings and other garden debris and household vegetable waste to make garden compost. This can be used as a planting compost or as a mulch to help keep weeds down and conserve soil moisture.
Mix grass clippings with coarser material to ensure your heap doesn’t turn into a sticky mess. Large pieces of plant material should be chopped up first to speed up the composting process.

As temperatures soar, make sure plants in your greenhouse are looking their best. Shading the glass will help keep temperatures at a bearable level. Damping down floors and surfaces will keep humidity high and also help deter red spider mite.
Ventilate greenhouses and conservatories on warm, sunny days.

Weeds can soon take over the garden, looking unsightly, smothering your prized plants and stealing valuable water and nutrients from the soil. Make sure you keep them under control before they become a problem.

Annuals and small weeds can be hoed on a dry or windy day. Make sure the blade of the hoe is sharp as the aim is to cut through the weeds’ stems.

Larger infestations and all perennial weeds, especially those with creeping roots, are best treated with a weedkiller based on glyphosate, which will kill the roots as well as the top growth. You’ll get better results if you spray in the evening. A thick mulch of organic material or using a planting membrane when planting up new beds will help keep the garden weed free.

Pests and diseases will be very active in the garden this month. Check plants regularly and keep on top of any problems that do occur to ensure they don’t get out of control – early eradication is the key to success. Ready-to-use sprays do away with fiddly mixing and ensure you have something ready to deal with the problems as soon as they are seen.Slugs and snails can still be a major problem this month. Make sure you protect susceptible plants, so carefully sprinkle slug pellets, place barriers or water on a liquid slug killer.

Remove blanket weed from your pond if necessary and put it on the compost heap. Buy a small bundle of barley straw from a water garden centre and place it in your pond to discourage algae. Split pond plants that have become overcrowded and are taking over the pond.

If you are going away on holiday, ensure your plants feature in your plans. If you can’t get a neighbour to look after your plants while you’re away, you could set up an automatic drip-watering system for your hanging baskets, pots, beds and borders and greenhouse plants.

Capillary matting is excellent for self watering pots both in the greenhouse and in the house. Houseplants should be removed from sunny windowsills and placed on damp capillary matting in the sink or bath.


Grow Your Own - Fruit

Keep wall-trained fruit, especially stone fruit, well watered during fruit set and fruit development to ensure they carry a good crop. Mulching fruit with a 7.5-10cm (3-4in) thick layer of organic matter will help retain moisture around the roots. Water all fruit if you experience prolonged hot, dry periods, giving one good soaking every week.

Thin apples after the June drop if the fruit is still overcrowded. Remove blemished and king (that is central) fruit from the clusters first.
Later in the month summer pruning of restricted apples and pears (such as cordons, espaliers and pyramids) can begin. In northern regions delay this until August. Cut back side branches longer than 23cm (9in) that are produced from the main stem to three leaves above the basal leaf cluster. Prune sideshoots arising from existing fruiting spur systems to one leaf beyond the cluster.

Branches of plum and greengage trees often collapse and snap under the weight of fruit produced, so make sure you support branches with heavy crops with a stout V-shaped stake.Cherries and plums can be summer pruned after cropping. Any branches growing out away from the wall should be removed entirely. Pinching out tender shoot tips, plus any sideshoots coming from the main stems, will prevent the trees from putting on too much leafy growth, ensuring good fruit production next year.

If you need replacement shoots for bare areas of an established plant, or if you are forming a new one, then select and retain one or two strong shoots at the base of the bare area, to train into these areas. Selecting two suitable shoots means you have some insurance in case the first shoot becomes damaged.

For wall-trained sweet cherries, pinch out the growing tip of each branch, once it has grown six new leaves. After fruit picking, the shoots can be cut back again, removing half of this year’s new growth, and removing any overcrowded or unhealthy looking stems at the same time. For wall-trained ‘Morello’ and acid cherries, prune out entirely any fruited shoots, removing all of this year’s new growth. But be careful not to remove any un-fruited new shoots, as these will produce fruit next year. Instead, tie them in so that they are easy to pick. Continue to tie in and train the new shoots of blackberries, loganberries and other cane fruit while they’re young and soft to prevent them being damaged by strong winds. Keep new shoots produced this year separate from the older, fruiting ones to make pruning later in the year easier.

Propagate blackberries and other cane fruits with long, lax stems by tip layering. Weigh down the tip of a shoot into the soil or a submerged pot of good compost with a stone. Only layer shoots from productive plants.

Cut back sideshoots on gooseberries to four or five leaves, or just beyond the fruit clusters. This will speed ripening by increasing sun on the fruit, encourage fruit bud formation for next year, and control aphids on the new growth. Red and white currants can be pruned in the same way.

When summer-fruiting raspberries have finished cropping, cut out the old fruiting canes to ground level. As new growth is produced tie it in to the supports. Don’t prune autumn-flowering raspberries; this is done in late winter. Hoe off or pull out raspberry suckers appearing between the rows.

Water strawberries regularly – especially plants growing in pots – and feed weekly with a high potash liquid feed. Watch out for slugs and birds, which love the fruit as much as we do. The easiest way to deter birds is to cover plants with netting. Put straw around strawberry plants to prevent soil splashing on to the fruit and spoiling it. Strawberries grown through black plastic don’t need strawing. If you need new strawberry plants, and providing your plants are healthy with no viruses, you can peg down the runners that develop on existing plants, to encourage them to root along the stem. Once rooted, the young plantlets can be severed from the runners and potted up individually and grown on ready for planting out in autumn.  Pick over strawberries regularly, removing any fruit that has started to rot to prevent infection spreading to others.

Sideshoots that form on pinched-out grape laterals (sideshoots) can be stopped at one leaf. Leaves that are shading grape bunches can be removed, to speed ripening of the clusters. Harvest indoor grapes when the skin becomes translucent.

Stop harvesting rhubarb to give plants time to build up strength for next year’s crop. Mulch with well-rotted manure and water during prolonged dry periods.

There are a number of fruit pests you should keep an eye out for this month.

Protect ripening fruit from birds; small trees and wall-trained fruit can be fairly easily covered with netting. Keep an eye out for aphid attacks, and deal with them appropriately, either by squashing small colonies, or by using recommended insecticides on larger infestations. Woolly aphids may be visible on apple and pear trees as a white, fluffy coating. It is best to treat them early, as they will only become more prevalent as the summer progresses.  Keep alert for gooseberry sawfly damage and the raised red blisters of currant blister aphid. Raspberry beetle can damage crops of raspberries and loganberries. Treat with an appropriate insecticide as soon as the first pink fruits are seen. Look out for powdery mildew on a range of fruit crops, especially during warm dry spells. Reduce attacks by keeping the soil moist, but the foliage dry.

Apples and pears may need spraying against scab, where this has got out of hand in previous years. Don’t spray pesticides once the flowers have opened as they may kill pollinating insects; sprays should be used before the flowers open or after the petals have faded. It’s better to spray early in the late evening when fewer pollinating insects are around.


Grow Your Own - Vegetables

There is lots to harvest in the vegetable garden, including spinach, peas, beets, carrots, salads and potatoes; shallots and spring-planted garlic may also be ready. Overwintered onions can be lifted and used. Pick courgettes regularly before they become marrows. Pick peas and beans as soon as they mature, to stop them becoming tough and stringy later in the summer and to ensure further crops.

Continue making successional, little and often sowings of all salad and quick-maturing crops to ensure a regular supply throughout the summer. Sow thinly within the row to reduce the need for thinning out once the seedlings are growing well. In hot weather, leafy salad crops may do better when sown in partially shady sites. Hot, dry weather can lead to bitter tasting leaves. Lettuce is best sown in the cool of the evening rather than when the sun is shining.

Sow spring cabbage, turnips, Oriental vegetables, chicory, fennel, and autumn/winter salads such as lamb’s lettuce. Carrots can still be sown, but beware carrot fly when thinning out seedlings Sow lettuce for an autumn crop. Choose a partially shaded place and water the soil along the rows before sowing the seeds. There’s still time to sow peas for a really tasty late crop. Towards the end of the month is the last chance to sow French and runner beans for a reliable late crop.

Plant out young leek and brassica plants for a regular winter supply. Ensure all vegetables get a regular, constant supply of water. This will help healthy development, and help to avoid diseases, disorders and bolting – running to seed prematurely.

Beans need sufficient watering to help the seed pods set and prevent them becoming tough and stringy. Water potatoes – especially those in tubs and barrels – when needed; if they dry out when the tubers are forming the crop will be significantly reduced.

Climbing beans may need stopping, to maximise cropping on existing sideshoots. Stop them when they reach the tops of their supports.
Summer cauliflowers may need shading to prevent the curds scorching in bright sun. Carefully bend larger, outer leaves over the curd.
Stop cordon tomatoes once they’ve reached their maximum height by removing the tip of the main shoot. Look for the leaf that's above the fourth truss and cut it off here. This should ensure that all the fruit ripens. Bush tomatoes can be left to their own devices.
Make sure they are kept well and evenly watered – if the soil or compost dries out then the crop is reduced, the fruit may split and even suffer from blossom end rot – where the bottom of the fruit turns black.

Tomatoes are also hungry feeders, and need a weekly diet of liquid tomato fertiliser. Remove sideshoots from upright cordon varieties.
And make sure plants are well supported – so tie them in regularly to their supports. 

Regularly water, feed and support aubergine, courgette, cucumber, marrow, pepper and squash plants to ensure they produce the maximum number of fruits.

Non self-blanching celery will need earthing up, after placing a protective collar of paper or cardboard between the stems and the soil.
Endive can be blanched to remove the bitter taste and make it sweeter by covering with an up-turned pot (with the drainage holes covered up) filled with straw to exclude the light.

Keep an eye out for pests attacking your crops. They can breed quickly, and early control will prevent them from getting out of control.
Pests such as caterpillars, aphids and carrot fly can be kept off a wide range of crops by covering with fleece or fine woven plastic mesh. Ensure that the corners are tucked in or buried to prevent the insects getting through.

Pinch out the tips of broad beans once they start to flower. This helps to discourage blackfly, which can be a problem on these plants.
Slugs are always a problem, so make sure slug controls are in place.

Pigeons are serious pests of brassicas and other vegetables, so use crop coverings to keep them away from vulnerable crops.

 


Grow Your Own - Herbs

For continual supplies of herbs like basil, coriander, dill and parsley, sow a small pot of each every fortnight.

Freeze fresh herbs, by snipping small pieces into an ice cube tray, filling the tray with water and freezing.
Trim bay trees to shape, then lay out the trimmings on a rack to dry for the winter.


Flower Power

If you have gaps in your beds and borders, now is a good time to plug them. Treat both you and your garden to some instant colour from summer-flowering herbaceous plants and seasonal bedding – there’s lots to chose from. And if your patio is looking tired or uninspiring, pop in some large container plants for instant impact. Keep all containers, but especially hanging baskets, well watered – they’ll probably need watering daily throughout the summer, especially during hot, windy or dry weather.

Feed flowering tubs, baskets and other containers with a high potash liquid fertiliser, such as tomato feed, every week unless you added a controlled-release fertiliser to the compost. Even then, a liquid tonic will produce extra flowering results. Containers based on foliage plants would benefit from a balanced feed.

As the flowers of bedding annuals, patio plants and herbaceous perennials start to go over, remove the faded flowers and any developing seedheads. This way they’ll go on flowering all through the summer. Follow up with a liquid feed to give them the boost they need to continue flowering their heads off.

If you didn’t get round to it last month, sow spring-flowering bedding plants for next year. All your spring favourites can be sown now – including wallflowers, sweet William, forget-me-nots, bellis daisies, polyanthus and primroses and winter-flowering pansies and violas – as well as more unusual types like ornamental cabbages.

Most types are easy to sow and grow on ready for planting into their permanent flowering positions – including containers – in the autumn.
Some – including wallflowers, sweet Williams and forget-me-nots – can be sown outdoors in a well-prepared seed bed. Simply make a shallow drill with a bamboo cane, sow the seeds thinly, cover with fine soil and water in.

Others will need to be sown indoors in pots or trays of compost and given gentle heat – preferably by placing them in a propagator.
Start collecting seed from plants you want to grow next year, especially annuals such as Calendula, poppy and love-in-a-mist. Perennials can also be grown from seed, but will take a year to flower. Keep the seed in a cool, dry place or in sealed containers in the fridge.
Towards the end of the month you can start to take cuttings of perennial patio and container plants ready for next year.

Take cuttings 7.5-10cm (3-4in) long, cutting below a leaf joint, or node. Remove the leaves from the lower one-third of the stem and insert in cuttings compost to the base of the leaves, spacing cuttings so the leaves do not touch. Then place the pot in a plastic bag (except pelargoniums) or in a propagator with bottom heat of 21-24C (70-75F) if necessary. Place somewhere out of direct sunlight to root.
Now’s a good time to take cuttings of pansies, violas and pinks for a supply of plants for next year. You can strike six or seven cuttings in a 10cm (4in) pot using a gritty cuttings compost or make your own from equal parts peat or coir and sharp sand or vermiculite. A hormone rooting liquid or gel will improve the results. Cover with a plastic bag or put them in a propagator and place out of direct sunlight. They’ll be ready to pot on in a couple of weeks.

If your bearded iris didn’t flower too well this year, then now’s the time to divide them. Cut off the flower spikes, then carefully dig them up with a garden fork. Select the largest fans of leaves with the healthiest rhizomes. Don’t bother with the smaller fans or very old rhizomes. Cut the leaves back horizontally about 15cm (6in) above the rhizome and trim back old roots. Dig a hole, large enough for the rhizome and roots; the rhizome should be placed at soil surface on heavy soils, a little below on light sandy soils, and firm soil around them.
Replant in groups about 30cm (12in) apart, 15cm (6in) for dwarf varieties. 

Prop up tall perennials such as lupins, delphiniums and gladioli if you didn’t stake them earlier in the year. Make sure that dahlias are staked before they need it - once they’ve fallen over it’s impossible to stake them so they look natural. Some late-flowering border perennials may benefit from a quick-acting feed before they come into bloom, especially if the soil is not very fertile.

Tie in sweet peas as they grow to ensure that they don’t flop and break their stems. Pick sweet peas regularly and certainly never let them go to seed or flowering will start to slow down.

Aphids can multiply rapidly during mild spells. Squash early attacks by hand to prevent the problem getting out of control. Protect sweet pea plants in particular, as they can get sweet pea viruses, which are transmitted by aphids and other sap-sucking insects.
Small holes and tears in new foliage of ornamentals such as caryopteris, fuchsia and dahlia are most likely caused by capsid bug damage. A systemic insecticide will help provide protection from these pests.

Continue to protect lily, delphinium, hosta and other susceptible plants from slugs and snails. Inspect lilies for the lily beetle as both adults and the larvae can strip plants of leaves and flower buds in just a few days. Vine weevil larvae can be a serious pest of containerised plants. Inspect the rootball of suspect plants, looking out for the C-shaped, creamy, orange-headed grubs. They are very destructive, but there are various chemical and biological controls available.


Trees, Shrubs, Roses & Climbers

This is not the best time of year for planting, but you can providing you look after the plants properly – ensuring they are kept well watered.

Dig a good sized planting hole, fork in plenty of planting compost and water the hole. Water the plant in its pot with a dilute liquid feed a few hours before you plant. If the roots are tightly wound round the rootball tease them out before planting. After planting water in with more liquid feed, mulch the soil and keep the soil moist until late autumn.

Ensure newly planted trees and shrubs do not dry out. Anything that was planted this year is prone to drought stress.

Other plants that can be vulnerable during dry weather are those that are shallow rooted – including rhododendrons, camellias, hydrangeas, heathers and conifers. A good soaking every 10-14 days is much better than a little and often approach.

Keep rhododendrons, azaleas and camellias in pots well watered, as it’s during the summer that they set their flower buds for next spring. Feed regularly with a liquid fertiliser recommended for rhododendrons and other lime-hating (ericaceous) plants.

Prune June-flowering shrubs, such as deutzia, philadelphus, kolkwitzia and weigela after flowering. Remove one in four of the oldest stems to ground level or just above a low-growing sideshoot or bud. After pruning give them a feed with a granular rose fertiliser. Lightly trim box trained in spires, balls or other topiary shapes. Fast-growing hedges, such as Leyland cypress, should be clipped as necessary throughout the summer. They can get out of hand very quickly. Regular clipping will keep them in shape.

Deadhead roses and other long-flowering summer shrubs regularly. Just nip off the flower head with thumb and forefinger rather than cutting off too much stem. Guide the new shoots of climbers in the direction you need them to grow to provide a good, even coverage of their support. Then carefully tie them in with string or similar material. Try to tie in the stems as near to horizontal as possible - or, if more suitable, into a fan shape. This reduces the growth of the shoot and, as a result, encourages more flowers.

To get the most from wisteria it’s important to build up a good framework of permanent branches to cover the support, so tie in stems as they grow. Now’s the time to give wisterias their summer prune. Cut back all this year’s leafy sideshoots to five to seven leaflets.After pruning feed with a potash-rich granular feed such as a rose fertiliser.

Remove reverted all-green shoots from variegated evergreens. These shoots, being stronger than the variegated ones, can soon take over and spoil the overall appearance of the plant. Cut them back to where variegated foliage starts or remove them completely.

Gently pull off suckers appearing around the base of grafted trees, shrubs and roses. It is far better to pull them off than cut them off, as dormant buds can remain when cutting and these will produce further suckers.

Take softwood cuttings of shrubs such as caryopteris, forsythia, fuchsia, hydrangea, kolkwitzia, lavender, perovskia, philadelphus, rosemary and spiraea. Use non-flowering sideshoots that have been produced this year. Cuttings should be 10-15cm (4-6in) long and taken just below a leaf joint. Remove the lower leaves to leave just two pairs of leaves at the top. Dip the cut end in hormone rooting powder/gel and insert the cuttings in pots of compost made from equal parts moss peat or coir and either sharp sand or Vermiculite. Seal the pot in a plastic bag and stand somewhere sheltered with good light but out of direct sunlight.

Clematis can be propagated by taking internodal cuttings – that is taking stem sections immediately above and 2.5-5cm (1-2in) below a leaf, rather than cutting the stem immediately below a leaf joint. They will root best if kept in a propagator with gentle bottom heat.

Layering is a good way to propagate many climbers and lax-stemmed shrubs. Layers should root by next spring. Choose a flexible shoot that can be bent down to soil level. Make a nick in the underside of the stem with a sharp knife at a node (where the leaves join the stem) where the stem touches the ground. Then dust the nick with hormone rooting powder and peg down the stem with a piece of bent wire or, better still, a small stone. Insert a small cane by the side of the stem and tie the stem to it to ensure it grows upright.

Caterpillars, aphids and most other pests can all become a problem at this time of year. Check plants regularly and deal with any outbreaks before they get out of control. Early infestations can be controlled by hand removal, but insecticides may be necessary for more serious attacks.

Check roses for signs of blackspot, aphids and leaf-rolling sawfly damage. Spray roses with a suitable fungicide to prevent black spot, rust and mildew diseases.

If the leaves of your camellias and rhododendrons have a black, sooty deposit on them, then scale insects – or a similar pest – is attacking them. Spray now with a systemic insecticide to control them.

In dry weather powdery mildew can play havoc with a wide range of plants, such as clematis, roses, honeysuckle and herbaceous perennials.

Keeping the soil moist will help keep this disease at bay, but in severe outbreaks it pays to protect plants with a systemic fungicide.

 


Luscious Lawns

Keep mowing the lawn regularly, except during drought conditions. In hot weather, set the mower at a slightly higher level than normal. This can help prevent the lawn drying out in hot weather. Leaving small trimmings on the lawn can help reduce water loss, but may lead to a build up of thatch that will need dealing with in autumn. Whenever you mow the lawn, trim the edges – it really makes a difference to the look of the garden.Cut uneven lawn edges with a half-moon edging iron to ensure they look neat and well shaped.

This is a good time to apply a liquid summer lawn fertiliser, especially if you didn’t give a spring feed. A liquid feed and weed or feed, weed and mosskiller may be useful if there are weeds or moss present.

Single weeds can be dug out or spot-treated with a lawn weedkiller. If weeds are a real problem it would pay to treat the whole lawn with a liquid lawn weedkiller.

If you want to have a really green lawn then you may need to water it once a week. Place an open jam-jar on the lawn and leave a sprinkler in place until 13mm (0.5in) of water collects in the bottom of the jar. Time how long this takes. This is the optimum amount needed without wasting water. New areas of grass, sown or turfed in the spring, will need extra watering to keep them going through their first summer.

 


Indoor Gardens

Water indoor plants regularly as and when they need it. Check plants every few days and water if necessary. Most plants prefer to slightly dry out between watering and overwatering is more of a killer than underwatering.

Water plants in early morning or late evening to avoid the risk of leaf scorch on hot days. Feed houseplants every seven to 10 days with a liquid houseplant fertiliser. If roots are peeping through the holes in the base of the pots, repot into a larger size. Flowering houseplants usually perform better if they are kept slightly potbound.

Check that houseplants are not scorched or drying out quickly by being left on a sunny windowsill. At this time of year many plants can overheat quickly and be damaged, so move them too a cooler spot.

Propagate Cape primroses (streptocarpus) by slicing a healthy leaf crossways into 5cm (2in) wide sections and placing the pieces vertically, 2.5cm (1in) deep, in a tray of compost. Place in a propagator and keep somewhere warm until you see new plants growing.
Make more African violet plants by carefully pulling off individual leaves with most of the stem and pushing this into small pots of fresh compost.

Cut the babies off spider plants and put them into individual pots to make new plants.

Some house and conservatory plants, especially orchids, ficus and citrus, can be put outside in a sheltered place for a ‘summer holiday’ to benefit from rain, fresh air and sunshine. Keep them well watered.

Clean shiny-leaved plants with a damp cloth to remove dust.

Regularly inspect plants for aphids, mealybug, red spider mite, whitefly, thrips and other pests. Control with a pest spray or use pesticide pins that can be pushed into the compost and will protect plants for several months.

Where feasible, damp down floors on hot days to reduce the risk of red spider mite. Alternatively, mist the foliage regularly or, better still, stand the pots on trays of damp gravel to increase humidity.

Copyright - Heritage Gardens 2019.

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