Garden tasks for June

This monthly guide is geared to London gardens and their unique conditions. Compiled by the RHS Wisley Plant Centre team
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Open hearth daylily
During June, check lilies, such as open hearth daylilies (above), for the dreaded lily beetle

Must do in your garden this month

* Sow bi-annuals such as wallflowers and foxgloves into pots or a nursery bed for strong plants to bed out in the Autumn ahead of flowering this time next year.

* As early flowering plants start to fade, give them good feed with something balanced, such as seaweed extract, to build the plants up for flowering next season.

* Make sure you are removing side shoots from tomatoes growing on canes to concentrate the plants effort into producing bumper crops.

* You can now lower the blades on your lawnmower and get summery stripes in your lawn.

* Bedding plants which have been planted out will also benefit from a dusting of a balanced plant food, such as fish, blood and bone or Vitax Q4. The feed in the compost that they were grown in originally will quickly run out and this top dressing will make sure the plants stay sturdy and resistant to attack by pests and diseases.

* Sow a second crop of peas to replace the first seasons’ pickings - sugar snap or mange-tout are ideal for a later crop and are less work as you eat the pod as well.

* Check lilies for the dreaded lily beetle - the adults are bright red, but the larvae disguise themselves under a layer of greenish slime that look like bird droppings. If you see holes appearing in the leaves either spray with a systemic spray, or jet wash the larvae off the plants for the birds to eat.

* In the greenhouse, make sure that you are letting enough air in to circulate around your plants to stop fungal diseases and also allowing pollinating insects in. Open the vents on warm days and make sure there is a low level of entry for cooler air by either leaving the door open slightly or with a louvre vent. Still close up in the evening to protect from night cold.

* Apples and pears will have what is called the “June Drop” when excess fruitlets are discarded by the host trees. This is a natural process and nothing to worry about, the trees are just keeping what they can comfortably support. Plums however sometimes over-crop and should be watched so that the weight of developing fruit does not break young branches.

* As blanket weed forms in ponds, use a forked cane to drag out as much as possible. Put the weed on the compost heap, it is a high nitrogen product which will help break the compost down.

Make a scented arbour around a favourite seating area, using canes or trellis and scented jasmine

Nice to do in your garden this month

* Sow some quick-flowering annuals such as phacelia, nemophila or linaria in gaps where you have cut back early flowering herbaceous plants so you have colour in the garden during August and September.

* Now is the time to be planting winter vegetables so your plots can be used all season. So many people let their vegetable patch go to waste over the winter period. With a bit of forward planning you can have fresh veg all year-round.

* Bats should be flying now, and planting evening scented plants such as Nicotiana will encourage moths that are a staple food source for these fascinating flyers.

* As early clematis finish flowering, prune back to the framework of the plants’ support - this encourages even growth so that the plant has flowers all the way up and not just at the top.

* Start a night patrol around your garden with a torch picking up slugs and snails. This is a very effective way of keeping these pests down and if you collect them in a sealable tub and leave until morning you can then open it onto the bird table for the birds to get the bounty.

* Cut back herbs as they start to get leggy - most herbs are better for a trim and the clippings can be used in bouquet garni.

* Plant a selection of salad leaf pots or window boxes, as the plants develop pull off leaves as you need them and this will keep them cropping until October.

* Make a scented arbour around a favourite seating area, using canes or trellis and scented jasmine or annuals such as sweet peas. Plant in large deep pots to give enough root run to the plants and enough support for the canes and enjoy warm, scented July evenings.

* Start a journal of plants you see now in gardens or at shows such as Chelsea so that you don’t forget to plant later in the year. Gardening is all about planning ahead - you will find this aide memoir invaluable in the autumn at bulb time.

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

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