The best weigela planting location is an open bed that gets full sun all day and has soil that drains well. Put the same shrub in two spots and the difference is hard to miss. A weigela in a sunny, open bed covers itself in flowers, while one crammed against a shady wall blooms thin and patchy. Sun is the single biggest factor, so pick the brightest spot in your yard for this full sun shrub.
Give your weigela at least six hours of direct sun and you will see the heaviest bloom this shrub can manage. More sun means more flowers, and you also get the deepest leaf color out of the deal. Plant a purple-leaf or variegated type in shade and you lose half of what you paid for, since the foliage fades to a dull green in a dim corner. Pick a spot that bakes in afternoon light and you get both the heavy bloom and the rich color you wanted.
Your soil matters almost as much as your light. Weigela wants well drained soil, but you can relax about heavy ground, since this shrub handles clay better than most flowering plants. Your real enemy is water that sits. Roots in a soggy bed rot, and you slowly lose the plant. If your chosen spot stays puddled for a day after rain, fix the drainage first or pick somewhere else. Even a clay-tolerant shrub needs its roots to breathe, so do not bury it in a low, wet pocket of your yard.
Stand in the spot at midday. If it gets six or more hours of sun and the ground is not still wet from the last rain, you have a strong weigela planting location.
Give your plant room to grow. A full size weigela spreads 9 to 12 feet (2.7 to 3.7 meters) wide once it settles in, and that width catches a lot of gardeners off guard. Set yours too close to a wall, fence, or path and you will be hacking it back every year, which cuts into next spring's flowers. Plant where that mature width has somewhere to go, and leave a few feet of breathing space on the side that faces your foot traffic. You want to walk past your weigela, not fight through it.
Match the variety to your spot so the size works for you instead of against you. Put a wide-spreading type in an open border or as a stand-alone shrub where it can reach full size without crowding your other plants. For a tight bed along the front of your house, skip the big forms and choose a dwarf weigela instead. The small ones top out near knee height and never overrun a foundation planting, so you get the flowers without the yearly battle. Read the tag before you buy and check the mature width against the space you actually have.
Think about your season, too. Weigela puts on a stunning show in late spring and then settles into plain green for the rest of the year. Drop yours into a mixed border and you let other plants carry the interest once the flowers fade. Tuck your weigela among perennials and later-blooming shrubs. It earns its keep in May and never leaves a hole in your view the rest of the summer.
Aim for that sunny, open, well-draining spot first, then choose a variety sized to fit it. Get those two calls right and your weigela asks you for almost nothing else for years. Land it in the wrong spot, though, and you are stuck with a thin, leggy shrub that never shows you what it can really do.
Read the full article: Weigela Shrub Care, Pruning and Varieties
