Gardening Help FAQs

Here are answers to some of the most common questions we receive about garden plants. You will find concise information on general gardening techniques as well as plant selection and care. For detailed information on specific plant pests and problems refer to our Common Garden Pests and Problems page.

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Horticulture Questions and Answers

How do I grow chrysanthemums?

Mums are photoperiodic with flower buds being initiated when periods of darkness extend beyond 12 hours each day. This situation occurs naturally outdoors when the days of summer become shorter as we gradually progress into autumn. Chrysanthemums can be divided into response groups with some cultivars coming into full bloom 6 weeks after the beginning of short days and others being much slower with full bloom taking up to 8 or even 10 weeks. It is interesting to note that generally all mums are hardy in the respect that the dormant plants will survive through the winter months. The reason some chrysanthemums are termed "non-hardy" is because they belong to the late flowering response group and even through the plants will survive the winter cold and temperature fluctuations, they flower much too late in the season and the blooms are subject to early frosts.

Mums will grow in any type of well drained garden soil rich in organic material. They should receive the maximum amount of sunlight possible with six hours daily being the minimum. Chrysanthemums are a welcome addition to the perennial border, their dark green and interestingly serrated foliage adding a contrast or backdrop for the summer blooming annuals and perennials.

Planting can be done in late spring or early summer with many nurseries now offering 4-inch pots of blooming chrysanthemums along with their spring bedding sales. These plants can be cut back after flowering and be allowed to become established in the garden during the summer. They will rebloom again in the fall. An alternative method is to purchase well budded or blooming plants in late September or early October and plant these in selected locations within the garden. Usually the late-season plants are grown in 8-inch or one gallon plastic containers. Being much larger, prices on these plants will be higher because of the additional time spent under the grower's care. Either size is quick to become established.

When transferring plants from pots to the garden, lightly disturb the root system before planting. Roots tend to become pot bound and this procedure will allow new roots to penetrate into the surrounding soil at a faster rate. Cover the top of the soil ball with no more than one-half inch of soil. Do not leave the top of the root ball exposed or plants will dry out rapidly. Water thoroughly and continue to monitor the watering for the next several weeks keeping the soil moist but not overly wet until the plants become established. An organic mulch should be used around the plants to prevent drying and to keep the roots system cool. The mulch can be left through the winter to protect from alternate periods of freezing and thawing. As the soil begins to warm in spring, new growth will appear from the base of the stems which had been cut back to 2 to 3 inches after flowering the previous fall.

If allowed to grow without pinching or cutting back, this new growth will become tall and weak with bloom occurring in early summer rather than autumn. This initial growth should be pinched halfway when it approaches 6 inches in height. A very easy and fast alternative to pinching is to shear plants with a sharp grass shears. This practice results in compact plants which are full of foliage and flower buds. The resulting growth from this shearing should then be cut back when it also approached 6 inches. Keep in mind, the finished plant height is controlled by the depth of the cut. A standard rule of gardening is to cease with this practice on July 15, however, shearing until the last week of July can be done without adverse effects. In a normal growing season, 3 to 4 major shearings can be done within the recommended time period.

Avoid fertilizers which are too high in nitrogen for they tend to promote excessively tall growth. Complete fertilizers such as 6-12-12 or 12-12-12 used at recommended rates through the growing season produce sterling results. Feeding should cease around Labor Day because plants will be setting flower buds and their need for nutrients has diminished.