Establishing a canopy for the planting of tender plants beneath it is a good thing. It traps radiant heat overnight during cold fronts keeping the plants a wee bit warmer. In the event of frost, rarely does it penetrate the canopy, which the tender plants really appreciate. The canopy is bad when it warms up, trapping the cooler air. Not enough sun light to warm the plants. Right now the crotons getting strong sun exposure are toasty warm. Touching the leaves you can feel the warmth. Crotons under the canopy, cool to the touch. Crotons in a shade house are probably getting perfect warming sun exposure. Shaded but warm, no wonder why crotons in a shade house look so good.