A Garden of Perennials needs to be carefully planned

When planning a garden with perennials you should consider hardiness, invasiveness, spread, self-seeding, and height.   Just as in landscape design you must have a vision of what the product will look like  years from the initial configuration. 

Of all the factors to consider, hardiness is the one which can have the most impact in the shortest amount of time.  The best way to ensure your plants will thrive in your garden is to purchase them from a nursery which has grown them locally.  Too often local nurseries may not have the varieties you are looking for or you just might want to try something new or original for the area.  To minimize the risk to your garden, identify a local perennial with the same characteristics which would also work in the garden location should your “experiment” turn into a flop.   Having a backup with a similar spread, height, and coloring will ensure you can recover should your original choice not survive.   Don’t forget that a component of hardiness is the plant’s resistence to local pests and diseases.    Powdery mildew can plague perennials and you should try to avoid plants which are more susceptible to this disease. 

Invasiveness is a key criteria when selecting perennials for a garden.   Invasive plants will spread into other plants which will require frequent maintenance.  If there is an invasive perennial you just have to plant then a good option is to put it into a container to limit the amount of maintenance your garden will require.

Self-seeding plants such as grape hyacinths can cause similar problems as invasive perennials.  By dead-heading the plants you can prevent their spread but that can be a risky proposition depending on the size of your garden.   It is best to avoid these if possible unless you are not bothered by the maintenance required by their presence.

Tall perennials will require staking. This can be a another maintenance headache depending on how many you decide to plant.  The primary concern with tall perennials is ensuring they are not planted in a shady location.  They will grow towards the sunlight which undoubtedly will cause them to grow at an angle.   Be sure to consider this when selecting the location for a tall perennial.