Horticulturist Christine Walkden visits the Beth Chatto Gardens and RHS Hyde Hall, and boards a vintage Thames sailing barge for a trip on the Blackwater Estuary.

Horticulturist Christine Walkden explores gardens and countryside from a hot-air balloon. In Mid Wales, Christine learns how to brace an ancient yew.

Horticulturist Christine Walkden explores gardens and countryside from a hot-air balloon. Christine takes to the skies above Yorkshire and visits Scampston Hall.

Horticulturist Christine Walkden explores gardens and countryside from a hot air balloon. Christine takes to the skies above Sussex and drops in at West Dean Garden.

Horticulturist Christine Walkden explores gardens and countryside from a hot-air balloon. Christine takes to the skies above Oxfordshire.

Horticulturist Christine Walkden explores gardens and countryside from a hot-air balloon. Christine visits England's northernmost county, Northumberland.

Horticulturist Christine Walkden explores gardens and countryside from a hot-air balloon. Christine visits Bodnant Garden in Snowdonia.

Horticulturist Christine Walkden explores gardens and countryside from a hot-air balloon. Christine's balloon odyssey takes her to the Borders region of Scotland.

Horticulturist Christine Walkden explores gardens and countryside from a hot-air balloon. Christine is in the air above two glorious Gloucestershire gardens.

Horticulturist Christine Walkden explores gardens and countryside from a hot-air balloon. Christine heads for the lakes and fells of Cumbria.

Horticulturist Christine Walkden explores gardens and countryside from a hot-air balloon. Christine floats over the landlocked Midlands county of Staffordshire.

Horticulturist Christine Walkden explores gardens and countryside from a hot-air balloon. Christine travels over the flattest part of Britain as she descends on Norfolk.

Horticulturist Christine Walkden explores gardens and countryside from a hot-air balloon. Christine flies above the green expanses of Hampshire.

Horticulturist Christine Walkden explores gardens and countryside from a hot-air balloon. Christine heads to the Scottish county of Aberdeenshire.