Spring

• Apply annual fertilizers in spring just as your shrubs begin to show signs of new growth. Use time-released fertilizers formulated for the type of shrub. Most shrubs require minimal water in spring since the soil is still moist from winter, but irrigate as necessary so the soil doesn't dry out. Apply a 3-inch layer of mulch or replenish the existing mulch layer as the soil begins to warm in late spring. Spring flowering shrubs are usually pruned after the flowering cycle completes, while other shrubs only need dead and damaged branches removed.
  
  

Summer

• Water management is your main concern in summer as the weather becomes dry and temperatures warm. Most shrubs need 1 to 2 inches of water a week from either rainfall or irrigation. Water once weekly deeply at the base of the plant, supplying enough water to moisten the top 10 inches of soil. Keep the area under your shrubs weeded so weeds don't compete with your shrubs for moisture and nutrients. Fertilize shrubs that require frequent fertilization at midsummer. Prune most summer flowering shrubs after they finish flowering. Some summer-flowering varieties bloom a second time in fall if they are pruned in summer. Other shrubs, especially those grown as hedges, may need maintenance pruning to maintain their size and shape.
  
  

Fall

• Begin preparing your shrubs for winter. Most shrubs don't require pruning in fall, and trimming too close to winter causes the shrubs to produce tender new growth that is killed by winter frost. Gradually begin reducing irrigation to deciduous shrubs as they begin to enter dormancy, but do not allow the soil to dry. Remove any broken or damaged branches as these are susceptible to winter damage and provide an access point for disease organisms and insect pests. Clean up fallen leaves and debris from the garden bed. Tender shrubs, such as some roses, need a protective mulch layer placed around them in late fall to prevent the crowns of the plants from frost damage.
  
  

Winter

• Dormant deciduous shrubs require little to no care in winter but evergreen varieties only enter partial dormancy so some winter maintenance is necessary. Water these shrubs during dry winter periods when the ground isn't frozen to ensure the soil doesn't dry out completely. Cold winter winds can desiccate the leaves and branches on evergreens. Construct a windbreak from burlap around the shrub or spray the leave with an anti-desiccant spray to protect them. Late winter is the time to prune many deciduous shrubs while they are still dormant, including roses and lilacs. Prune these after the buds begin to swell but before they begin leafing out. Prune most evergreens in late winter just before new growth begins.