Stock is highest in Autumn. Delicate lilies and daisies are typically in Spring. Coastal stock is typically available outside of Winter.

Think about your site conditions and design.

This will help you to choose from the stock available at the time.
If you have multiple conditions, split your garden into sections.

Plant health

Soil Type: clay, loam, sand, salty.

Sunlight: full sun, part sun, shade.

Water: rainfall, irrigation.

Garden design

Purpose: decorative, edible, animal attracting.

Plant Size: height, width (shrubs are approx. equal to height or wider x1.5).

Access: are people walking on it or past it in tight spaces?

Focus: experimentation*, survival*.

Example garden requirements.

1 – Hills: clay, part sun, high rainfall, irrigated.
1 tree, 5 small plants, walked on groundcover, flowering.

2 – Coastal: sand, full sun, mid rainfall.
Trees, and small plants for butterflies.

*Experimentation – You may find unexpected plants that can grow in your garden.  They may need more care and might have higher losses.
*Survival – The plants should be well suited to your garden and require less care (after a year). Plant types will be closer to the historic plants and ecosystems. There will be fewer plants to choose from.