Answer: Rose petals are sensitive and one reason would be that when the weather is very hot and the rose bush doesn't get enough water, the petals can show damage. Red roses plus multi-colored ones are very prone to burning in hot sun no matter what you do. A thick mulch would help as roses love cool roots and the mulch keeps the roots cool and damp.
Keeping arborvitae healthy is simply a matter of watering deeply once a week during the growing season.
Browning grass is usually due to the grass variety. Cool season grasses (which make up most of the lawns in the Pacific Northwest) die out when the weather gets warm but green up again when it gets cool in the spring.
Hope this information helps.
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