MAY 15 and the RULE 2-4-6
What do these have in common? One is our frost-free date (on average May 15) and the other determines how much sunlight a plant needs. We are still not frost-free. To be frost-free, we must reach 40° continuously at night. We still have many annuals that can handle the cooler temperatures. In addition to pansies, snapdragons, alyssum, diacia, dianthus, stock and lobelia can all handle cooler temps.
Determining the right plant for the amount of sunlight in a particular area of your yard can be tricky. The 2-4-6 Rule helps you decide what will grow best in a particular spot. Less than 2 hours of sunlight is considered deep shade; 2 to 4 hours is part-shade; 4 to 6 hours is considered part-sun and over 6 hours is full sun. Deep shade is probably the most difficult. I recommend tuberous begonias. These are amazing performers and do not require a lot of water. It is best to water the pot when the surface of the soil is dry.