In your ornamental garden in August 2011

Herbaceous border
in summer

General tasks

August is often a time for sitting back and enjoying your garden and all that hard work you have put in. Time to relax in your deckchair, put your feet up and listen to the birds singing and the insects buzzing. Don’t forget the sunscreen.

But even in this lazy month, there are some jobs that really must be done.

• Water hanging baskets daily
  • Water baskets and small containers daily even if its raining! Rain will bounce off the leaf canopy. Even in a downpour, little rain will reach the potting compost and the plants’ roots. In a really hot spell and full grown basket may need watering twice daily.
• If your rain water barrels are overflowing in a rain storm, don your rainwear and rush out and use the water so there is room for more! Shrubs, roses, fruit bushes and so on will all benefit from a bit extra to drink, particularly those against a wall or fence.
  
• Keep the garden performing well
  • 
    A stroll around the garden, secateurs or scissors in hand, is a pleasant way to spend some time.  With just a little attention you can smarten up the  plants and encourage many to produce a second flush of flowers while you wander. Don't take off just the flower head, trim back to a leaf joint. This keeps the plant tidy, and is less likely to result in dieback. Remove any dead or damaged leaves to prevent attracting fungal pathogens and to make your plants look their best.
  • Roses always benefit from regular dead-heading, unless you want them to produce rose hips. Prune rambler roses when flowering is over.
  • If annuals flowers are allowed to set seed, they will tend to stop producing new flowers. Showy plants, such as petunias, will flower all summer long if dying blooms are removed, and seedheads not permitted to develop.
    
  •  On the other hand, you could leave some to produce seed to collect for sowing next year. A great  money saving activity.
  • Pick sweet peas every other day to prevent them from setting seed, even if your vases are already full. The more you pick, the more flowers will be produced.

Greenhouse and conservatory



In the hot summer sun, temperatures can be, literally, scorching under glass. Provide shade, and plenty of ventilation so that plants don’t suffer. Damping the floor down daily will help lower temperatures, and improve growing conditions. But avoid splashing water onto leaves. That just gives fungal diseases, such as mildews, a chance to germinate. Make sure plants don't go short of water or nutrients - a stressed plant is more likely to succumb to pest or disease attack.

• Continue to feed pot plants until the end of the month.

• Pot plants benefit from a top dressing of leafmould, or some other soil conditioner.

• Pests such as red spider mite can build up rapidly in these hot conditions, so check daily for infestations. Be prepared to order biological controls and rub off pests while you wait for them to arrive. Don’t be tempted to use any sort of spray while you wait, as these predators are super-sensitive to residues, even organic ones.
• Fungus gnats (Sciarid flies) can be a problem in pot plants. These pests thrive on moist, organic material in potting compost. Reduce watering, and top dress the compost in the pots with coarse grit or fine shingle to maintain a dry surface. Only water from below. Disturbing the leaves can cause the fungus gnats to fly up and hover by a window. Suck them up with a hoover! It’s very effective. Buy in the Sciarid fly control Hypoaspis to consume the larvae and break the lifecycle. Garden Organic members can view our organic factsheet on sciarid fly in the Members' area of this website.

   

A wide range of biological control agents, to control a range of pests, is available from The Organic Gardening Catalogue.

Garden Organic members, see our organic factsheet on Biological controls (online access to factsheet requires members' password)

Lawn care

• In hot weather allow grass to grow a bit longer. About 3cm (just over an inch) is ideal. It will survive dry spells much better. Remember, grass is a drought survivor. Save the water for more important areas.
• Try leaving the box off the mower, and let the clippings fly. They will rot speedily in warm weather, returning valuable nitrogen to the growing grass. You'll save time and effort if you don't have to go back and forth emptying the mower box.
• Don't bother to water your lawn in dry spells, even if it starts to develop brown patches. It will recover very quickly when the rain does come.
• If you are thinking of buying a new mower, consider a 'mulching' or 'recycling' mower. These machines chop up the mowings very finely, then spread them evenly over the lawn. No more clumps of mowings walked into the house, and much time saved not having to empty the grass box.

Pond management

• 
  Keep your pond topped up in hot weather. Rainwater is best, but you can use tap water if it is urgent. If possible, leave tap water for 24 hours to sit  before use to allow some of the chemicals it contains to evaporate. As tap water can be rather rich in nutrients don’t use it if your pond tends to grow algae.
• Rake out any blanket weed, but don’t throw it on the compost heap immediately. Leave it by the side of the pond for a couple of days, so any creatures caught in it can return to the water.
• Make sure you have oxygenating plants in your pond so creatures can breath. A small fountain or cascade can also help keep your pond oxygenated. The sound of trickling water can be very relaxing too. Now that solar powered pumps are available, there is no need for an electricity supply.
• Keep your eyes peeled for water-lily aphids. The best way of dealing with them is to simply blast them off with a jet of water from a hose.

Spring bulbs. Bulbs such
as crocus and wood
anemone are a good
early source of food for bees

What to plant in August

• Towards the end of August, plant bulbs for flowering next spring. Try planting Narcissi (daffodils) in lawns or under trees for a natural look. Plant them in drifts, rather than singly and choose smaller, less showy types. Select an area where you can afford to leave the grass long in the spring until the leaves have done their work to build up next year's bulb.
• Other native spring flowers such as snakeshead fritillary, Fritillaria meleagris and cowslips, Primula veris will give a natural look to your planting. Ensure that any bulbs that you purchase, especially native species, are from a guaranteed source and not plundered from the wild.
Cultivated and wildflower bulbs  are available from The Organic Gardening Catalogue
• Other native spring flowers such as snakeshead fritillary, Fritillaria meleagris and cowslips, Primula veris will give a natural look to your planting. Ensure that any bulbs that you purchase, especially native species are from a guaranteed source and not plundered from the wild.
  Cultivated and wildflower bulbs are available from The Organic Gardening Catalogue

Make new plants

Clematis can be layered now.
Pull down a flexible stem. Make a small notch at a node (where the leaf joint sprouts from the stem). Bury this node under a small pile of soil and keep this moist. Leave it until next spring, then check to see if roots have developed from the node. Once roots are visible, you can sever the top part of the stem from the parent plant. You now have a new plant.

Seed saving

• August is a good month to start saving seed. When you dead head to keep the flowers coming, leave just a couple of flower heads to go to seed on your favourite plants.

  • Look for seed heads that are turning brown and papery.
  • Cut them from the plant, pop them in paper bags, labeled with the plant names, then let them finish drying indoors. Shake the seeds out into the paper bags once they are dry
  • Always store seed in an airtight container, in a cool dry place. Wardrobes make very good storage places. If you've bought seeds this year, and not used the whole packet, as long as you store them somewhere cool and dry, they will probably still be viable next spring.
  • Some seeds, such as geranium, need to be collected before they are ripe as they have an explosive dispersal mechanism. You can simply cut the dead heads off and put them in a paper bag and leave it on a sunny windowsill. You will hear the seeds fire against the side of the bag.

  Plan ahead
  It’s easy to spot gaps now, for example where you’ve cut poppies back. Why not sow seeds of a quick crop such as cut and come again lettuce? They’ll fill in the gaps quickly, provide you with tasty salad, and can be easily removed if you want to plant the gap with bulbs, or another perennial. 

Easy perennials

This is a time when some gardens can look a bit sparse for colour and many large gardens actually close to the public. Garden Organic Ryton has always been a continuing riot of colour all through the summer and into the Autumn with real quality perennials and later flowering annuals.

• Coreopsis grandiflora is a lovely and very reliable plant with yellow ragged single flowers held above a tidy clump of blade-like leaves. It stays pretty much free of pest and disease and is loved by bees and hoverflies. There are quite a few cultivars worth trying too, ones like: Coreopsis grandiflora "Early Sunrise" that is golden and double, C. grandiflora "Mayfield Giant" which is just like the species but with a much larger flower.

• The late anemones are very reliable and pest free, some can get a little bit of powdery mildew but rarely enough to spoil them. See our Powdery mildew factsheet in the member's area for more information. Anemone japonica and all it's varieties are excellent choices. A. japonica "Bressingham Glow" is a particular favourite with delicate semi double flowers that are pretty popular with wildlife too.

• For grand and spectacular effects, Cynara cardunculus is a must, with it's bold deeply cut grey foliage and huge thistle blue flower spikes to 2m, this plant is a real showstopper.

• 
  Bees, hoverflies and butterflies love Echinacea
  
  
  Cosmos at their best

• One of the most popular later flowerers is Echinacea purpurea, this American prairie plant has become widely know for it's medicinal properties. Commonly known as the coneflower, Echinacea have a central cone with petals radiating out. Good varieties are E. purpurea "Magnus", with deep purple petals and an orangey cone and E. purpurea "White Lustre" with pale greenish white petals and a golden cone.

• It is very hard to talk about late flowering perennials without mentioning Penstemons and Penstemon "Alice Hindley", a beautiful plant with a low habit and the loveliest blue and pink flowers that just go on and on and on, a big winner with the bees and hoverflies.

• Annual Cosmos will always add lots of colour in late summer and they are so easy to grow. Simply sow a few seeds direct in the flower bed in the spring and wait for the stunning show in August.

 

 

Pest and Disease Watch

• 
  Cut back mildewed pulmonaria
  leaves. They will soon regrow.
  
  
  Rose leaf with powdery mildew

• Look out for powdery mildews. They are common when weather conditions are warm and dry during the day and cold at night, and on dry soils. They are often most severe at the end of the growing season. Plants in a ‘rain shadow’ are very susceptible. Anything growing under roof eaves, or close to a fence or wall will often succumb.
  
  Powdery mildews are caused by various species of fungi. They can affect trees, shrubs, roses, perennials, annuals, bulbous plants, vegetables, fruits and many indoor plants. Each species of powdery mildew affects only specific types of plant. A few plants are susceptible to more than one type of powdery mildew.

  See our Powdery mildew factsheet for more information on diagnosis and control of this fungus.
  
  (Online access to factsheets requires members' password - find out about becoming a member here)

• Collect any rose leaves showing signs of black spot. Nip them off the bush, and pick up from the ground. This will clear spores away and reduce the level of the disease.

• Aphids can still pose problems on some plants. Be vigilant and manually wipe out any new infestations. If populations increase then blasting them off with a hose works well or as a last resort spray with safe sprays such as insecticidal soap based on fatty acids (available from the Organic Gardening Catalogue).
  

  Sprays approved for use in the organic garden can be harmful to useful insects, so only use them as a last resort.
  Spray flowering crops at dusk when bees are not active. Always follow the manufacturers instructions when making up and using sprays.

  Read the label before you buy. Use pesticides carefully
  See our aphids factsheet for more information
  
  (Online access to factsheets requires members' password - find out about becoming a member here)

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