How to Prune. Your outdoor cannabis plants should be at least 3-4 feet tall by June 27. Growing marijuana outdoors gives bigger yields when you trim and shape your plants during the first weeks of summer. Pruning dead and spent flowers, foliage, and stems encourages healthier, fuller plants … Dormant pruning is especially important for apples, pears, and crabapples because pruning wounds during the growing season expose the trees to a bacterial disease called fireblight. Throughout the growing season, prune liberally to create a compact and lush plant that will generate constant new growth or prune more conservatively if desiring a taller, less-full plant. If you aren’t pruning each type of plant in your garden, you should choose the tool you need to prune the plants you do grow. Prune forsythia, rhododendron, and lilacs for shaping or size control after flowering. Test Garden Tip: To control the spread of diseases while pruning, dip your pruning shears in rubbing alcohol or a solution of one part bleach to nine parts water. These plants form next year's buds during the summer, so belated trimming cuts off those future buds. Tools You Need to Prune. Pruning Vegetable Plants – Prune lower branches of tomatoes and peppers early on to allow light and air to the plant An overgrown garden is an open invitation to disease and pests. You will need three different tools to prune. Not to mention, it makes it difficult for plants to perform to their maximum potential. Using clean, sharp pruning tools, remove all branches and sucker shoots within 1-2 feet of the ground. They’ll be used for different types of plants. Outdoor yucca plants may grow taller and bushier than what is desired for the rest of your landscape, but proper pruning will help you keep your outdoor yucca plants looking neat, healthy and well-tended. Pruning Shears Here are the tools you need: 1. Step 1 Remove any dead or damaged leaves by hand at the end of summer, gently plucking them off the plant.