Submitted by Krista Harding
Just like last year, we have been gotten a lot of rain this spring. Our soils were definitely saturated for several weeks. You may think that watering won’t be needed for quite some time since soil moisture levels are very high. However, watering may be needed much sooner than you think.
Excessive rain can drive oxygen out of the soil and literally drown roots. Therefore, as we enter hotter, drier weather, the plants with damaged root systems may be very susceptible to lack of water. Don’t forget to check your plants for signs of wilting or leaf scorching and water as needed.
My annual flowers haven’t been overly impressive yet. I know as our temperatures warm, they will pick up blooming speed. To keep the blooms going, a nitrogen fertilizer application and removing spent flowers is a must. An application of fertilizer is especially needed this year considering the amount of rain we have gotten recently.
Modern annual flowers have been bred to flower early and over a long period of time. Providing nitrogen through the growing season (sidedressing) can help maintain flower display. A high nitrogen sidedressing should be applied four to six weeks after flowers have been set out. Additional fertilizers every four to six weeks are also helpful during a rainy summer or if flower beds are irrigated. Common sources of nitrogen-only fertilizers include nitrate of soda, urea and ammonium sulfate. Use only one of the listed fertilizers and apply at the rate given:
Nitrate of soda (16-0- 0) – Apply ¾ pound fertilizer per 100 square feet
Urea (46-0- 0) – Apply ¼ pound fertilizer per 100 square feet
Ammonium sulfate (21-0- 0) – Apply ½ pound fertilizer per 100 square feet
If you cannot find the above materials, you can use a lawn fertilizer that is about 30 percent nitrogen (nitrogen is the first number in the set of three) and apply it at the rate of 1/3 pound per 100 square feet. Do not use a fertilizer that contains a weed killer or a weed preventer.
Removing spent flowers or “deadheading” will help some plants bloom more profusely. Annuals focus their energy on seed production to insure that the species survives. If old flowers are removed, the energy normally used to produce seed is now available to produce more flowers. Deadheading is as easy as pinching the plant between the thumb and finger, but tough, wiry stems will require the use of scissors or pruning shears.
Plants that do increase blooms in response to deadheading include: hardy geraniums, coreopsis, some petunias, marigolds, snapdragons, begonias, some roses, zinnias, sweet peas, salvia, blanket flower and yarrow.
There are some “self-cleaning” plants on the market now. These plants drop their spent flowers and bloom again and do not require manual deadheading. In many cases they are sterile varieties – bred not to produce seeds. The petunia and rose varieties that are “self-cleaning” continue to excel in the home garden market because of their low maintenance and blooming power.
If you need help with any horticulture topic, give me a call. My current office schedule is Monday, Wednesday, Friday – Erie; Tuesday – Iola; and Thursday – Fort Scott.
Krista Harding is a K-State Research and Extension Agricultural agent assigned to Southwind District. She may be reached at 620-244- 3826 or kharding@ksu.edu