Prepare container-grown perennial shrubs and small trees for the summer months. These plants have already suffered during April’s prolonged dry spell and, who knows, it could continue.

But whether that is our fate or we endure the more usual driech, wet summer, we must give our pot plants the best chance. The starting point is knowing the needs of different plants. How much to feed them, how thirsty they are, and how they handle temperature fluctuations?

The thermometer can fluctuate madly just now, with grey, drizzly days followed by glorious ones with blossom-frizzling night frosts. I hope you weren’t caught out last weekend and had protected the less hardy specimens.

Use a south-facing house wall to act as a storage heater for long enough to ward off an early morning frost. Alternatively, simply drape a piece of fleece over the plant. However you do it, H4 shrubs, like hardy fuchsias, may need some shelter, except in the most favoured coastal areas in the west of Scotland.

Apart from fruit bushes and trees, most container-grown perennials have been bred to cope with a less nutritious environment. But to thrive during adverse weather conditions, they must be kept healthy and that means giving them the feed they need.

Mediterranean herbs like rosemary, prefer gritty soil with little nutrient, while a rose needs an annual top dressing of compost. On the other hand, as with all flowering shrubs, overly generous feeding encourages vigorous leaf growth at the expense of flowers. Plants are often stimulated into flowering when times get tough as they rush to flower and set seed.

Fruit trees, and to a lesser extent, bushes, are a different matter because of the nutrients required to produce good fruit. The soil must be kept fertile and never allowed to lose structure. This entails gently scraping off and replacing the top 30cm or so of compost. Clearly home-made compost is more nutritious and long-lasting. Do this any time from March to May.

Good soil structure retains moisture whereas gritty clapped-out stuff lets the water rush straight through. Like a pint of refreshing beer on a summer’s day, it scarcely touches the sides.

When this happens to one of my Pelargoniums, I remove the plant from the pot letting much of the dry grit fall away. This leaves space to line fresh compost on the base. After repotting, I cram fresh compost down the sides.

When repotting, check the compost to see water spreads equally throughout the pot, removing any broken crock at the bottom as this impedes drainage. Compost on the sunny side of a pot will be drier so should be replaced.

Even undemanding plants like Pelargoniums, lavender and dwarf conifers including Pinus pumila need some water. My potted gooseberry and blueberry are drouthier souls, and my peach house acts like a huge container, so the tree calls for a frequent soak if we’re to get any fruit.

Always give a plant a good soak less frequently rather than a daily dribble, increasing the amount as it grows or forms fruit. During a dry spell, place saucers under pots to retain water but remove them and raise pots off the ground with pot feet or a couple of old slates during prolonged wet weather.

If you have an irrigation system, modify frequency and duration of applications, but I swear by hand watering containers. I control exactly what different plants need.

During lockdown, many of us have plenty time, and if you’re a home teacher, watering provides a perfect switch off. Why not give the children a break from the screen and teach them about plants and watering?

Plant of the week

Geum Hannay’s Flowers have soft orange centres with darker veins running to the scarlet flushed tips of the petals. Plants make a tight mound of attractive leaves and are easy to grow in a sunny spot.