For annual sunflowers (plants that bloom only once), no pruning is typically required. However, sunflowers growing in clusters may need to be pruned to prevent them from spoiling on others. Instead, perennial types of sunflowers will occasionally require a trim. Pruning helps these plants maintain a neat and tidy appearance during the summer months when they tend to get unruly. To prune plants correctly, you first need to know when to prune them.
Steps
Method 1 of 2: Knowing When to Prune
Step 1. Cut perennials twice a year
A good general rule for pruning perennial sunflowers is to cut them down to half their size in late spring or early summer. Then, reduce their size by another third in June or July.
Step 2. Remember the warm weather
Gardeners in warmer climates must prune Maximillian, submerge the Helianthus angustifolius sunflower in water and prune Helianthus salicifolius sunflowers to two-thirds of their original height in June.
This procedure will keep these potential giants in a more manageable format and eliminate the need to prop them up
Step 3. Avoid pruning after the first blooms appear
Most perennial sunflower species bloom in mid to late summer. Gardeners should keep an eye on their plants during this period and refrain from pruning them after the sprouts begin to form.
However, the rules are slightly different for varieties that bloom in late summer. The types that bloom in late summer should be pruned when they reach a height of 45 - 60 cm, because they can recover in a few weeks and flower regardless of the cuts
Step 4. Prune very tall sunflower varieties in June or July
Maximilian sunflowers (Helianthus maximiliani) and Mexican sunflowers (Tithonia diversifolia) should be cut in June or July. This will reduce the size of the sunflowers from their typical height of 2.70 meters or higher, to a more manageable height of 1.20 meters.
Maximilian sunflowers can be left as they are during the winter months as bird food. If you choose to leave your tall sunflowers for the birds, they can be pruned to the ground in spring to prepare the plant for new growth
Step 5. Know that annual flowers will not bloom again
Annual sunflowers can be pruned to the ground when they begin to dry out and turn brown in color. They won't bloom again so many gardeners choose to remove them from their gardens completely.
Method 2 of 2: Prune Your Sunflowers
Step 1. Sterilize all pruning tools before use
Sterilizing your pruning tools is especially important if you have recently used them with some diseased plant parts. Sterilization will prevent persistent bacteria or germs from unintentionally spreading throughout the garden.
Prune sunflowers with sturdy hand pruners or hedge trimmers
Step 2. Cut the diseased parts of the plant first
Trim all diseased, weak, damaged, twisted or dead branches from your plant before starting any type of heavy pruning operation.
The diseased parts must be kept out of the compost bin to prevent the disease in question from being transmitted to all other plants. Instead, this debris will have to be burned or put in bags and left available to be collected with the waste
Step 3. Prune the perennials to the desired shape
Once you've cut off all the diseased branches, you can choose to prune your perennial sunflowers for shape.
Some just prefer to cut off the damaged parts of the plant for their sunflowers to take on a more natural look
Step 4. Water your plants after you have pruned them
Water the sunflowers regularly after pruning to help them recover from the stress of the process. Water enough to wet the soil thoroughly whenever the top part of the soil becomes dry.
Advice
- Once gardeners have completed their cuts, they should oil their garden tools to prevent them from rusting. The garden tools must then be kept in a safe place so that they can be easily found for later use.
- Sprouting the upper shoots on these plants is a somewhat effective method of reducing the height of the plant. Even if the lateral shoots will form blooms, the plant will not grow in height.
