How to plant both spring and autumn flowering perennials?

If the autumn bloomers are planted in the spring or therabouts, and are in flower through the autumn, when can the spring flowers be planted? During autumn the bed will be full of the autumn flowering plants, and in spring how can you plant the autumn flowerers without disturbing the flowers currently in flower?

 

There are two ways of achieving successional flowering. One way, as I mentioned in your other post is to ensure compatable plants spaced so that they can all thrive without the need to move them.

The other way seems more in line with this post. In parts of my garden I run a two shift system. I grow all my plants from seeds and cuttings, but you can use bought plants. I grow a number of biennials - these are plants that grow during one year, but don't flower till the next. I grow plants like wallflowers, Hesperis (sweet rocket), Dianthus barbatus (sweet william), Lupins (which I treat as a biennial), Foxgloves and Lychnis coronaria etc. Because they have been building up their strength in the first year, most biennials flower relatively early. After flowering they can be replaces by late flowering plants, such as annuals like Cosmos, Cleome and Tithonia, perennials that you can grow as annuals such as Salvia coccinea, Salvia patens, perennials that I have grown from cuttings taken in the previous winter and plants grown from tubers such as Dahlias, Mirabilis, Cannas etc.

I sow my biennials into pots early in the year. About now I will be lifting my tubers (eg Dahlias) and pulling out the plants grown as annuals. But only after having collected seed for next year and taken cuttings. So now I will be planting out my biennials, which are all hardy and still in their pots. When these have done flowering around early summer next year, I will remove them (after taking seed) and throw them away, and replace them with the Dahlias and annuals. The key to this is to grow plants in large pots, and then plant them out at a relatively late date. If you plant a pot grown plant, you hardly disturb it at all. But you must grow things in as big a pot as possible.

 

I really appreciate this detailed answer!