Garden tasks in July

This monthly guide is geared to London gardens and their unique conditions. Compiled by the RHS Wisley Plant Centre team
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Bearded irises
As bearded Irises finish flowering replant their stems to encourage next year's growth

Must do in your garden this month

* Dead-head roses as the first flowers fade, cut back slightly to encourage new growth. Top-dress with a balanced rose fertilizer such as Toprose. On standard roses, remove any growth or suckers coming from the stem or base to stop the plant being weakened.

* As bearded Irises finish flowering, lift the clumps if they are congested and split. Replant the rhizomes (stems) just on the surface facing the sun with the fan of leaves behind. This ensures the rhizomes get baked which will encourage flowering.

* Prune June flowering shrubs, such as Weigela, when they have finished flowering to encourage next year’s growth and top dress as with roses.

* Put conservatory plants outside in a shady spot for a holiday while the weather is warm - this then gives you a chance to clean the plants of any pests and also clean the conservatory.

* In the greenhouse or cold-frame it is time to take semi-ripe and stem cuttings while the shoots are in full growth. Use rooting compound on all but geranium cuttings.

* Harvest potatoes when the plants start to flower and store them in a dry, dark place. You can now get ‘potato bags’ which exclude light from the stored tubers but allow air to circulate around the crop to stop any rot setting in.

Nasturtium seed
Fill any gaps in your baskets of bedding plants with nasturtium seed
* Bedding plants in baskets and planters will need dead-heading. If there are any gaps in the display, push in some nasturtium seed which will quickly germinate and fill any holes in the display.

* Apples and Pears will have had their ‘June drop’ but you still might need to do some more thinning to get the best fruit. If there is a cluster of fruit always take the “king” or central fruit-let first to let the rest develop.

* Give your lawn a liquid feed if you didn’t in the spring - a lawn gets a lot of traffic at this time of the year and will benefit from a bit of TLC.

* Cut back to five leaves or last fruit-let on any side shoots on gooseberry, red and white currants - this helps the plant to put all its effort into fruit production.

Nice to do in your garden this month

* As new canes of blackberry, loganberry and tayberry develop, tie them on the horizontal to space the crop of fruit for easy picking.

* Peg down some of the runners off strawberry plants to get young plants for next year. Use 10cm pots with good compost, set the small runner plant on the surface of the compost and peg down with a piece of bent wire. When rooted in six to eight weeks, cut the plant off the mother plant. Strawberry plants need to be changed on a three-yearly basis so this is a good method of keeping your stock productive.

* If you haven’t invested in a water-butt now is the time to get one and save water for using on your flowers and vegetable plants. Slim-line versions are available for those with small gardens.

If your greenhouse is empty, sow some courgette plants for a late autumn crop
* Order catalogues for next years bulb display. Some bulbs, such as snowdrops, should be planted in August as soon as they become available.

* Compost as much green waste as possible, remembering to add compost accelerator every six inches to help the heap break down without using up all the nutrient content.

* Although it seems a bind at this time of the year, fences and wooden structures should be at their most dried out in July, so a coating of wood preserver will penetrate deeper into the wood to give longer life to them.

* If your cold frame or greenhouse is empty why not sow some courgette plants for a late autumn crop.

* While the weather is warm take your houseplants out into the garden, wrap their pots in polythene bags to prevent the plants being overwatered and then lightly wash over the plants to remove any dust or grime that will have accumulated in the crevices of leaf joints or branches. Check for pests and diseases, prune out any excess growth and then return to their place in the house.

* The ash from your barbecue is a great source of potash, but it is too strong to use directly on your plants. Either add to your compost heap every few inches or leave in a pile in a corner of your plot for about six months and then you should be able to use this to get plants to flower.

* Visit Hampton Court Flower Show (Hampton Court Palace, East Molesey, Surrey) for inspiration and gardening gadgets, from July 6-11, 2010.

All images provided courtesy of the Royal Horticultural Society. Visit the online print shop at

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