Summer in the Castle Garden
by Jason Hanslip
Summer Garden Tips from Jason Hanslip, Head Gardener at Bolton Castle
Bolton Castle, near Leyburn in North Yorkshire, opens to visitors from spring to autumn every year, and Jason and his team have their work cut out to keep the gardens looking their very best. With over 1,000 metres of hedging, including a maze, rose and herb gardens, a dyers garden, a small but perfectly formed vineyard, as well as lawns and flower beds to maintain.
Here are his recommendations for all gardeners over the summer.
Hoe, hoe and hoe
This should be one of your top tips for the summer months. If you hoe once a week and get the weeds when they are small, it’s amazing how much time you save. Weeding little and often is the trick!
Watering
If you’re planning on going away this summer, place some trays under your containers and fill with water – the plants will soak this up when they need it. We do this with our tomato plants it works wonders.
When watering borders, use water wisely. Water the base of the plants, giving them a good soaking once a week rather than a little bit everyday. Whilst you’ve got your hosepipe or watering can out, top up your bird baths, ponds and water features – this really does help the wildlife.
“Traditionally ‘The Derby’ horserace is a great reminder that it’s time to start cutting box hedges”
Box hedging
Traditionally ‘The Derby’ horserace is a great reminder that it’s time to start cutting box hedges as all the risk of frost has passed (well, 99 percent). Pruning regularly will give your box that classic topiary look and remember to regularly clean tools to prevent infection. Many of us often experience the feathery cobweb- style covering which affects our Boxwood plants, and its family of plants. Known as Box Blight, Boxwood is particularly suspectable giving our hedges unsightly brown leaves and stem die back. This fast-spreading fungal disease is caused by two types of fungus; Cylindrocladium buxicoa and Volunterra buxi. The Box Caterpillar is also a constant threat. Box tree moth/caterpillars are relatively new to the country but are becoming invasive very quickly. The moths are active over the summer months, with the caterpillars overwintering in the hedges. The first signs of an infestation is clear webbing over the plants. Following this the plants will start to lose foliage, becoming very bare, and, if not treated the plants may die. However, thankfully by taking a few steps the damage can be avoided or kept to a minimum. We recommend using pheromone traps from April, or start as soon as you can, and changing the lures every month. This will catch the male moths and also give a good indication of how active they are. If caterpillars are present, Jason recommends using Steinernema carpocapsae nematodes which are a great biological control as they reproduce spreading to other affected areas.
As with any plant damage its always advisable to give the plant some fertiliser to help it recover from the attack.
Roses
To get the best out of your roses make sure you give them a feed after their first flush of flowers but more importantly, keep dead heading them to keep the plant producing flowers.
Sweet Peas
If you have visited our tearoom during the summer months you will have smelled these beauties as soon
as you walk in. The secret to growing sweet peas is to keep cutting them; the more you cut the more they will flower. Also, keep removing the tendrils – this will stop them getting all tangled up and ensure you regularly tie them in.
Flower Borders
One of the main jobs to do is cutting back geraniums and delphiniums in order to get a second flush of flowers later in the year. Once the lavender has finished flowering, trim it back so that it keeps its shape. Now is also the time to think about next year’s flowers such as foxgloves, forget me knots, and wallflowers which are biennials so they need to be sown now to flower next year.
Kitchen garden
Things should be in full swing so keep up with harvesting and watering as well as mulching which is a great way to retain moisture and keep the weeds down. Keep your eye on your courgettes as they can turn
to marrows in a blink of an eye. Keep removing side shoots on tomato plants to keep them under control, along with feeding every few days with a high potash feed. Cover your cabbages and cauliflowers with a fine netting to keep the cabbage whites out. Lastly start easing up on harvesting the rhubarb as it needs to start storing its energy for next year’s crop. If any flowers pop up, remove these as soon as possible.
Follow Jason Hanslip on Insta gardeningwithjase. Bolton Castle is open to visitors until 31 October 2025, with a programme of events and activities, including falconry displays and re-enactment days, most included with entry. Visit boltoncastle.co.uk for more details.
NorthernLife June/July/Aug 25
