Sunflowers are very large which makes them susceptible to strong winds and storms. Staking a sunflower is a good way to stabilize the plant and keep it unharmed when bad weather hits. The following will provide you some tips to keep the stalks of yours growing strong.
Step 1 - Set Up the Stakes
While it's true that even very large sunflowers can stand up on their own, windy weather often causes drooping. In fact, it's quite common for some flowers up to 14 feet tall to stand up without assistance. It's recommended to stake a sunflower only to protect it from the elements. Staking a plant keeps it safe in windy conditions, which is especially important if your area is prone to strong winds on a regular basis. If your sunflowers are located near a tree line, fence, or building, staking can also help in the event that these surrounding structures fall and cause damage during inclement weather. A really bad storm can destroy a whole crop of sunflowers if you aren't careful.
To properly stake a sunflower, you need a large bamboo pole or rod driven into the ground to attach it to. Prepare for these stakes by starting small holes along the length of your flowerbed, before planting the sunflowers themselves. If you dig or place stakes into the ground after the sunflowers have begun to grow, you risk damaging their root system.
Step 2 - Choosing a Size of Stake
Purchase the sunflower stakes from a garden center or nursery. Bamboo stakes come in a wide range of sizes, from a few feet all the way up to 12-foot poles. For sunflowers, it's a good idea to use stakes that will end up being about half the size of the grown plant, so for smaller varieties of sunflower, which only grow six to eight feet, use stakes of about three or four feet. For giant sunflowers, consider using a full 12-foot bamboo rod with a very large diameter.
Step 3 - Drive the Stakes
Drive each bamboo pole into the holes you've started, using a mallet if necessary to make sure it is at least a few feet into the ground. Because the purpose of staking is to keep your sunflowers secure, it's very important to make sure the stake is firmly planted in the ground.
Step 4 - Tying the Stakes
Tying the sunflower to the stakes is an important step, but one that can't be started until your plants have begun to grow. Make sure you don't tie the sunflower too tightly, as this may cause damage by choking out the plant. Secure the flowers to the poles loosely, leaving a space that is a little bit larger than the width of the stem. This will give the sunflower enough room to move around. Also be sure you use a non-abrasive cord or string that won't cause damage to the stem of the sunflower.
Step 5 - Try Mounding Instead
Another way to prevent a sunflower from falling over is to create a mound around the base of the plant. Mounding is done by putting topsoil or composted manure around the sunflower. This secures the roots and helps prevent the sunflower from uprooting in strong winds.
Dig a pit at the beginning of the year when you start planting, and then continue to fill it up as the plant grows larger. If you don't want to dig a pit, simply place dirt around the sunflower on level ground. Mounding promotes root growth and adds a lot of nutrients to the soil. Spread a large bank of compost manure around the base of the plant every few weeks, making sure to level the soil as much as possible so it won't wash away during a storm; you don't want to expose the roots of the sunflower to the open air.