Arranging plants of different heights in your urban planter boxes is key to creating a dynamic, lush, and healthy mini-garden. The most effective and visually pleasing method is often called the "Thriller, Filler, Spiller" technique, adapted for linear planters.
Start by placing your tallest "Thriller" plants at the back or center of the box, depending on whether it's viewed from one side or all around. These are your structural focal points, like ornamental grasses, tall snapdragons, or a small evergreen shrub.
Next, add mid-height "Filler" plants around the Thrillers. These bushy plants add volume and color, filling the middle layer. Excellent choices include begonias, geraniums, or herbs like rosemary.
Finally, let "Spiller" plants cascade over the edges of the planter box. These trailing plants soften the container's lines and add length. Consider ivy, sweet potato vine, or trailing lobelia.
Always consider the plants' sunlight needs and growth habits. Ensure taller plants don't shade out sun-loving smaller ones. Plant in odd numbers for a more natural look, and don't overcrowd—allow space for growth. With this layered approach, you'll create a professional-looking, thriving urban garden display.