This month, with long days and warm temperatures, growth is at its maximum. Roses are in full swing and the garden is at its fragrant best. Highlights in my Devon garden include the tall spires of foxgloves, serving as a reminder that now’s the time to sow seed again for next year. Early honeysuckle scents the garden during evening, we’re just starting to pick the first mouthwatering broad beans and early potatoes are nearly ready to lift.

in the vegetable garden...

- Plant pumpkins, squash, marrow and courgette plants into well-cultivated soil. If you don’t have a veg plot, slot them into gaps in borders or plant one courgette into a large patio container.

- Make a second sowing of sweet corn into modules. Plant out 30cm x 30cm (12in x 12in) and you’ll be harvesting towards the end of August. Plants are wind-pollinated, so it’s important to plant in groups or blocks rather than in a straight line, so the pollen can circulate among the plants.

- Weed between strawberry plants, place straw around the plants under the developing fruits and stretch netting over the bed. This will protect the ripening strawberries from blackbirds. Beware of untidy netting, as birds can get caught in it.

in the flower beds...

-  Add bedding plants to borders where spring flowering plants like forget-me-nots have finished. Set large kinds like spider flower (cleome) and cosmos 35cm/14in apart and smaller snapdragons, zinnias and marigolds 25cm/10in apart. Used informally, in groups, they make colourful gap fillers.

- Plant out dahlias raised or bought in pots. They’ll need good, well-cultivated soil and a handful of general purpose fertilizer each. Water each plant in really well and watch out for slugs.

- Treat sweet peas to a liquid feed every week. Keep picking the flowers, or at least remove those that have faded. If you let them go to seed, they’ll stop flowering and the plants will start to die back.

and in general...

- Move potted rhododendrons, azaleas and camellias out of harsh sun. Water regularly using rain water, but if you run out, tap water is better than none. Add a liquid feed for ericaceous plants to the water every two weeks to keep the leaves nice and green.

- Look out for plain green shoots coming from variegated shrubs such as pittosporum, holly and elaeagnus. Prune them out, or they’ll take over.

- Pot herbs into a large container and place in the sun as close to the kitchen as possible. Mix rosemary, sage and thyme, but give mint or parsley a whole pot to itself. 

QUESTION TIME

Q What do I do about the white powdery patches appearing on my rose leaves?

A Powdery mildew is a common rose disease, unlikely to kill your plant. If you’d wanted to spray with a fungicide, the best time would have been back in March. I don’t spray, but keep roses moist and mulched. Those very badly affected are replaced with healthier types. The shrub rose ‘Roseraie de l’Hay never suffers from mildew or black spot.