|I began growing Yarrow, Rudbeckia, and Blanket Flower in a bed facing southwest this Spring. They get afternoon sun only b/c of tall trees. All are supposed to be drought tolerant (once established). Mine literally get scorched by the sun and fall over if I do not water them every day. We've had little to no rain this year near our home (zone 7). Are mine just|
|As your plants mature they will have larger root systems and will require less water. You can encourage deep rooting by watering deeply when you do apply water. The deeper the root system, the less often you'll need to water. Try weaning them off so much water by applying water slowly so it has a chance to trickle down and wet the entire root mass (a sprinkler set in place for 15 minutes should do it). Wait 2-3 days and dig down into the soil. If it is still moist 2" beneath the surface, you won't need to water for a few more days; if it is dry, it's time to water again. Eventually you'll get a feel for how often to water - once or twice a week is all your plants should need, even in the hottest part of the summer. Plants that wilt in hot afternoon sun don't necessarily need water. They are simply protecting themselve from excess water evaporation and will generally perk up overnight. Don't let wilting be a prompt for watering; check the soil moisture first (as described above) before watering your plants.
Hope this clarifies things for you.