My buddy Jeff can joke all he likes about stakes in the garden.  I really know that his #1 choice is a lean T bone.  

Where your perennials and some flowering shrubs are concerned you have a stake (pun intended) in their performance this time of year. Truth is, if you wish to see your delphiniums bloom next week you should really give them some support now.  Otherwise they will fall over in the wind or under the saturated weight of rain-filled flower blossoms.

The exercise is simple:  find a piece of lumber or buy a stick wire stake and some twine to hold flowering plants up in an upright position.  It is not that your peonies or hydrangeas will not bloom without the support.  Rather, you will just miss them as they lie on the ground: out of sight.

To not stake your tall growing flowering plants this time of year would be a shame.   You have, after all, waited all year for this brief respite from snow and cold to enjoy the best colour that your garden has to offer all year long.  

By the way, I have 27 antique hydrangea Annabelle (introduced to Canada in 1888) growing in my front garden.  I take the time to support them all using lots of twine and stiff metal stakes.  The results are magnificent!