Past Articles Library | How to Grow and Care for Larkspur
Larkspur is the annual version of Delphiniums, which are commonly found in English cottage gardens. If you live in an area that has cool springs followed by moderately warm and wet summers then you can successfully grow Delphiniums. On the other hand, if your summers are warm then you would be better off utilizing the larkspur. Even though the larkspur is an annual, it will easily reseed itself for many years of enjoyment.
The name Larkspur comes from the shape of the flower. The flower of the Larkspur consists of five petal like sepals that form a hollow pocket, which has a spur at the end. The flowers can be found growing in a multitude of colors, which includes purple to blue, red, white and even yellow. The flowers themselves are supported on tall spikes that can reach two to six feet in height. This is why this flower makes a great colorful backdrop to any landscape design.
Larkspur can be a challenge to grow from seed but with these following tips, you will find that your seed germination rate increases. The first step of this process should occur in the early spring and consists of site selection. Delphiniums can tolerate partial shade but really showcase their wares when planted in full sun. Once you have your site selected, the next step is to properly prepare the site. This is done by removing any unwanted plant material. After that is done, turn the soil and mix in two to four inches of well seasoned compost.
The step involves seed preparation. What this means is we need to mimic the outdoor environment to get the seeds to germinate. In the Larkspur, this means you will need to refrigerate the seeds for 24 hours. Once this time period has passed, take the seeds out of the refrigerator and soak in room temperature water for 3 to 4 hours before planting.
After the seeds have received their treatment, the next step is to plant the seed. Since Larkspur is considered an annual, spacing is not that critical. As a matter of fact, this plant really shows off when it is planted in clumps verses rows. In doing so, simply broadcast the seed over the soil surface and sprinkle the seeds with less than ¼ inch of soil. Water the seeds in gently and monitor the soil moisture consistently until you see evidence of seed germination. Do not expect anything for 15 to 21 days.
If you want to get a jump on the flowering season, start the seeds indoors. To give enough growing time between starting inside and planting outside, make sure to start the seeds six to eight weeks prior to your local frost-free date.
Once the seeds have germinated, add your plant support. While this may seem a little premature, it is easier to do it at this stage then waiting until you need it.
If you do not want to take the time to start Larkspur from seed or you are afraid that you will not get the results you would like, take a trip to your local garden center. Larkspur plants are easily found.
When it comes to planting Larkspur plants, the process start by preparing the soil as described previously. After that is done, the next step is to simply dig a hole twice the width of the container and the same depth. Next, tip the pot upside down and gently tap on the bottom. At this point, the plant should fall into your hands. If that does not happen, squeeze the sides of the pot and turn upside down again or just cut the pot away from the roots. Gently tease the roots with your fingers and place in the hole. Prior to filling in, make sure the depth is equal with the top of the root ball. Once the depth is correct, fill in the hole with soil, gently tap down, and water in. Add the plant support.
Continue to monitor soil moisture and apply additional water if the soil dries out and/or your area receives less than one inch of rain a week. As the growing season moves on, feed the Larkspur with a balanced fertilizer every three weeks.
To keep the plant and flowers looking their best, deadhead the spent flowers back to flowering side shoots. Since the flower stalks can be so tall, tie them to the supports that you added earlier in the season. As stalks are cut and new ones develop, do not forget to adjust the plant supports as needed.
Larkspur is susceptible to a few plant problems. These include slugs, powdery mildew, gray mold, and rust. Slugs eat holes in the leaves of the Larkspur. While this may not seem like a big deal since Larkspur is an annual, the damage from slugs makes the plant look unsightly. The best way to get rid of slugs is through a slug trap. A simple one is to just set out shallow dishes of beer throughout the garden. Another trap that you can make is one that only requires you to lay out boards and/or cardboard around your plants. Prior to the morning sun rising, go out and flip the boards or cardboard over. What you will find on the underneath side are slugs. Remove these creatures and place them in a plastic bag. Place the bag in the freezer and freeze for three to four hours. Once they are frozen, place your slugs in the compost bin.
If you find white, circular patches on the top of the older leaves of your Larkspur, chances are you have powdery mildew. Believe it or not, powdery mildew is a fungal disease that is not caused by wet vegetation. These patches will continue throughout the plant and eventually distorted the blooms and flowers. The best way to control this problem is to only plant powdery mildew resistant varieties but if you find that your Larkspur plants already have the symptoms, pull up the plants and toss out.
Gray mold, on the other hand, is caused by excess moisture. Plants with gray mold will have white spots that appear on the leaves and these spots then turn gray and finally brown. This spot will continue to grow until it takes over the entire leaf. As the plant disease continues to grow, it will cover leaves, buds, and blooms. To prevent this problem, be careful when handling plants and deadheading. Gray mold will set up in plants that are weak from damage. While you cannot control when it rains, you can manage when you water. To allow the plant material to dry off prior to nightfall, only water in the morning.
Rust is another plant disease that is caused by a moist environment. How do you know if your plant has rust? Take a look at the leaves. If you see white or yellow spots on the top of the leaves or orange red like blisters that go through to the underneath side of the leaf then you have rust. The best thing you can do if this disease is present is to pull up the effected plants and throw them away. On the other hand, if you want to prevent your Larkspur from developing this problem, take care when you water.