Q. Two out of my 3 bottle brush bushes look dry and yellowish. The first 2 years they were fine. Does it mean they are not watered enough? Bottlebrush flowering Bottlebrush after Winter cold damage Bottlebrush with yellowing due to iron chlorosis A. Many plants in general, including bottlebrush, can be damaged if watered either too often or not watered frequently enough. If you are going to error about watering, it is better to give plants too much water than water them too often. But I think the problems iron, not water. Right now water plants like this once or maybe twice each week at the most. Yellowing of the leaves can also happen because of real low winter temperatures. Similarly, it can also happen if the soil is not improved or covered in rock mulch. Bottlebrush don’t like rock mulch at all and if they are planted in rock mulch they frequently turn yellow in 3 to 5 years. If they get yellow enough, the leaves begin to turn brown and scorch. This is what I think happened to your plants. Purchase an iron fertilizer and apply it to the soil above the roots now and water it in. The best iron fertilizer contains the letters EDDHA on the label or in the ingredients. EDDHA iron chelate is an important for iron product to use in desert soils. Iron applied to the soil will only improve the green color of new growth. The older leaves which are yellow can only be improved with an iron fertilizer solution sprayed on the leaves. Spray this solution in one week intervals until you get a dark green color. If these are growing in rock mulch, buy good quality compost, not a soil mix, and spread it around each of the plants and water it in. Apply around one to one half cubic foot of compost to the base of these plants and water it in, even in rock mulch.