The inside guide to pots with oomph Last week, at the Garden Museum's Lots in Pots auction, a planter designed by Arabella Lennox-Boyd fetched £500, the highest price of the evening. The money went to a good cause, the bidder went home with a spectacular white brugmansia surrounded by white annuals - and Arabella's reputation as a purveyor of extraordinary pots was assured. Arabella says: "I try to make all my planters exciting, original and fun - a pot should be full and exuberant. I use them often to anchor a design or to give balance to a space as well as to extend interest throughout the year. Shown here are two pots she created for clients: a minimalist clipped box topiary and a maximalist mix of grey foliage plants in a lead trough. For long-term pots such as these, Arabella recommends starting with a generous drainage layer of pot shards, gravel or stone. Place geo-textile fabric over this (to prevent soil from filtering in) then fill the pot with soil-based compost. Feed plants regularly with a slow release fertiliser such as Osmocote. Tiered box This simple but effective pot is achieved not by clipping one large shrub to shape, but by planting small box plants in concentric rings. Start with three plants in the centre at 35-40cm high. Surround these with plants 30cm high, then use 25cm tall plants for the outer ring. All are best rootballed and spaced 15cm apart, but if space is tight, use bare-root plants. Clip after planting to establish tiers at the correct heights and encourage bushy growth. Then clip twice or three times in May, June and August. The box can stay in the pot for several years. Study in grey In the lead trough below, Arabella used purple-flowered Salvia leucantha, grey-leaved Artemisia 'Powis Castle" and trailing Helichrysum microphyllum. She added five per cent horticultural grit to the compost to ensure free drainage. In the case of the salvia and artemisia, start with large (2-3l) plants. They grow rapidly and will put on a good show in the first year, provided they have sun. The planter is very impressive from about late July well into October. The artemisia is hardy but the salvia will need lifting, potting and protecting in winter. The helichrysum, usually sold as bedding in 9cm pots, is easily replaced annually. For a range of terracotta pots, see arabellalennoxboyd.com/products Online Special offer: white borage seeds for only £1.99 gardenshop.telegraph.co.uk