The two first aesthetic considerations I have with garden design using plant material are form and texture. Don’t burden yourself straight off with trying to select specific plants in your compositions.
Take an overall view of the space you’re designing, and think in terms of forms or shapes that would achieve the look you envision.
For example, here I had a narrow planting area between a bluestone walkway and a raised wood deck. My garden design objective was to diffuse the view underneath the deck while creating a soft and gradual introduction to this tall wood structure.
Thinking of form and not specific plant varieties, a climbing vine would accomplish the lower screening and create the gradual, soft connection I was looking for between the ground and the deck – and all within this narrow planting space.
Once I had decided a climbing plant would work well, I then began to consider my choice of vine based on other considerations such as growth habit, exposure, soil type, etc. Climbing Hydrangea was the plant I chose.
The planting space remaining at the base of the climbing hydrangea would be limited for this garden design.
Thinking in terms of form again, I pictured the climber set in a lush bed of foliage. Here I chose Ostrich Fern and Variegated Hosta. Their textures contrasted beautifully (fine and coarse) and gave the vine its own identity with its simple glossy leaf (medium texture).
Don’t let the specific plant choices get in the way of your vision. If you have to, design with just form and textures in mind and then head to the nurseries to look for specific plants that fit your vision.