Gardeners’ World 2021 episode 16

Gardeners’ World 2021 episode 16: Adam Frost adds tall plants for shady conditions to his borders, shows us how to make a window box for growing vegetables and herbs, and gives his tips on how to grow plants successfully in peat-free compost.

Nick Bailey visits Kew Gardens to explore their collection of ferns, and we return to the urban garden of Kate Bradbury to find out how she ensures that visiting wildlife is kept well fed throughout the summer months. We travel to the Isle of Man to a garden where a range of exotic plants are thriving in the microclimate on the island and meet a nurseryman in Kent with a passion for hydrangeas.

Gardeners’ World 2021 episode 16

Shade gardening

Shade, due to trees or buildings, is an almost inevitable part of gardens and gardening. Understanding that plants respond differently to shade and that a wide range of shade situations are likely to be encountered is invaluable in planning and planting a garden.

Shade is the blocking of sunlight (in particular direct sunshine as opposed to diffuse light reflected from the sky) by any object, and also the shadow created by that object. To grow healthy plants in shady areas, it is important to match the degree of shade that a plant needs or will tolerate with available light. Unfortunately very few plants will thrive where shade is very dense, particularly when coupled with a dry impoverished soil.

All green plants depend on sunlight to manufacture the sugars that go to providing energy for the plant and for making the organic molecules that make up plants. Shade leads to lower sugar production and reduced growth and flowering and ultimately, in plants ill adapted to shade, death. Plants can ‘measure’ shade by using pigments that can detect far red and blue light and modify their growth habit in proportion to the degree of shade.

Plants can be considered as ‘shade avoiders’ and ‘shade toleraters’, to a greater or lesser degree. Sunlight is a mixture of wavelengths but the presence of shade alters the balance of colours which sophisticated systems within plants can measure and alter their growth according to the shade that they encounter.

Plants for shade – Gardeners’ World 2021 episode 16

Gardens shaded by trees and buildings are increasingly common as gardens get smaller. Although north- or east-facing gardens can be cool and shady for much of the year, they can present some creative opportunities with well-chosen shade-tolerant plants.

Ferns

Low-maintenance and tolerant of a wide range of soil conditions, ferns complement any shade plant combination. From tiny specimens grown in walls to the royal fern at six feet tall, there’s room for ferns in every sized garden. Most ferns are easy to grow and will thrive in any moist, well-drained, shady site in well-dug, humus-rich, neutral to alkaline soil. However, those such as the royal fern Osmunda regalis, require neutral to acid soil.

Ferns do not usually require feeding when planted in the open garden, but mulches such as well-rotted farmyard manure will condition the soil and give a boost to growth. Where soil conditions are particularly poor a well-balanced fertiliser, such as Growmore or fish, blood and bone can be added in spring. Water when necessary, but apply to the roots and not directly to the fronds or crown as this can encourage rot.

Ferns make good companions for other hardy perennials in containers. Use a mix of 3 parts peat-free multipurpose compost, 1 part John Innes No 3, and 1 part gritty sand by volume. When first potting the ferns, incorporate a controlled–release fertiliser. The following year use a general fertiliser such Miracle-Gro during the growing season.

How to grow shrubby hydrangeas

There are a number of different hydrangea types but they all enjoy similar growing conditions. They vary in size from small shrubs to sizeable, almost tree-like specimens so check the plant label when buying to get one that is suitable for your space. Which hydrangea you choose will likely depend on your preferences for flower colour and/or shape.

Mophead and lacecap cultivars of Hydrangea macrophylla (and also Hydrangea involucrata and Hydrangea serrata) change colour depending on the acidity or alkalinity of the soil (pH) that affects aluminium availability. Those with blue or pink flowers tend to be blue in acid soils (high available aluminium levels), mauve in lightly acid to neutral soil conditions, and pink in alkaline conditions. White, red and green-flowered cultivars, remain white or green regardless of soil pH.

Plant your shrubby hydrangea soon after purchase. The best time to plant is in spring or autumn. Containerised plants can be planted all year round as long as the soil is not frozen, too wet, or excessively dry in summer (but you can water them well if you really want to plant them then).

Summer lawn care – Gardeners’ World 2021 episode 16

At this time of year, the lawn is actively growing and how you look after it depends on what you want to achieve. To encourage wildflowers for pollinating insects, it’s time to stop mowing and enjoy the visits to the flowers that appear. To create a short, green sward, however, you’ll need carry out of range of tasks we explain below.

No longer are all lawns green and striped. Over the last few decades, many gardeners have come to love the joys of seeing and supporting the insects and wildlife that visits long grass.

In mid-spring (often late March to April), use a proprietary spring or summer lawn fertiliser at the manufacturer’s recommended rates. Feeding the lawn will increase vigour and help prevent weeds and moss from establishing. Apply fertilisers when the soil is moist, or when rain is expected. However, it’s important to know that fertilisers use a lot of energy to make, so using the minimum required to keep your lawn in shape is best for the environment.

If grass loses its vigour and freshness between late spring and late summer (often May to August), repeat the application of spring or summer lawn fertiliser or apply 15g per sq m (½oz per sq. yd) sulphate of ammonia mixed with four times its weight dry soil. Mixing with soil ensures even distribution and avoids scorching the grass. Apply this mixture in cool, moist conditions and lightly water it in. As an organic alternative, use chicken manure pellets. Repeat fertiliser application a third time if needed six to eight weeks later.