Alan's perennial size guide

Small square pots (7-9cm)

Young plants with small rootballs, widely available from garden centres in spring and usually the size sent out from mail order nurseries.

• Pro: cheap and more reliable than bare-root perennials
• Pro: wide range available by mail order from specialist nurseries
• Pro: ideal for planting large drifts in borders or as groundcover
• Con: still best to pot up and grow on before planting out

These plants are usually one year old and cost approximately £2-£4.50.

Standard pots (1-2 litre)

The standard garden centre sales size. Sold all year.

• Pro: good value for money
• Pro: garden-ready and easy to establish outside
• Con: smaller garden centres offer limited choice of varieties at this size
• Con: often sell out quickly when in flower and are then not available again until the following year

Plants in standard pots are usually two to three years old, and cost £4-£9.

Large pots (3-5 litre)

Often sold seasonally at garden centres when the plants are looking their best.

• Pro: instant impact
• Pro: perfect for making focal points and features in a border or large container
• Con: very limited range available
• Con: need careful soil prep and aftercare to get established
• Con: high price

These plants are usually three to four years old and cost approximately £8-£20.

Looking to buy shrubs or trees for the garden? Take a look at Alan's shrub size guide and tree size guide, so you know what to expect for the price you pay.