Horticulture 2023 Newsletter No. 45

Horticulture News



Blog Post: http://www.ksuhortnewsletter.org

Video of the Week: Protecting Roses for Winter



Kansas Turf & Landscape Conference

The 73rd Annual Kansas Turf & Landscape Conference will be held on Wednesday, November 29 and Thursday, November 30 at the Hilton Garden Inn, Manhattan. The conference is an excellent way to learn about turf and landscape management, visit with old friends, network with new ones, and see all the latest products and supplies from local and national vendors.

The conference has been approved for commercial pesticide recertification hours:

1 Core hour

3A – 7 hours

3B – 7hours

GCSAA education points and International Society of Arboriculture CEUS will also be available by attending the conference.

For more information, go to https://www.kansasturfgrassfoundation.com/


Remove annual flowers killed by frost.
Plant spring-flowering bulbs.


Winterizing Roses

Although most shrub roses are hardy through Kansas winters, many hybrid teas and other modern varieties require protection. It is important to wait to winterize roses until several hard frosts have occurred, but prior to the ground freezing. Too early and the stem remains warm moist; good conditions for cankers to develop. Too late risks damage to the sensitive graft union where the rootstalk attaches to the above ground growth.

Clean up plant debris in the area surrounding the roses to prevent diseases from overwintering. Mound soil or compost eight to ten inches high around each rose plant. Bring in new soil for this rather than displacing soil from the area around the roses to avoid damaging the roots and exposing them to the cold.

Once the ground has frozen, add a 4-inch layer of straw, leaves, wood chips or other mulch over the mound and cover with a layer of soil to hold it in place. This will help protect the plants from the cold but also prevent early budding during warm winter and early spring days. As the mulch settles during winter you may need to add more.

Prune canes to 36-inches and remove weak or thin canes. Tie the remaining canes together loosely to keep them secure during windy weather. If the canes are allowed to whip in the wind it can cause damage to the crown and disturb the soil.

When the ground thaws in the spring remove the mulch and soil from the base of the plant to return the soil level to normal. (Cynthia Domenghini)

Amaryllis Culture

Amaryllis (Hippeastrum) are a classic bloom for this time of year. If you are purchasing bulbs be sure to select the largest bulbs available that are firm and dry. If growth is visible it should be bright green. Each bulb should produce three to four blooms on a one to two-foot stem. Larger bulbs will produce more flowers.

Amaryllis grow best in tight spaces so select a container that is about one-inch larger in diameter and twice as tall as the bulb with drainage holes in the bottom. Hold the bulb over the container with the roots dangling to the bottom and add a sterile potting mix. Firm the soil around the roots carefully to avoid damaging them. Leave the top third to half of the bulb visible above the soil.

Put the container in a sink and water thoroughly. When the water has stopped draining, set the plant in a warm, sunny location. As the flower opens move the plant away from direct sunlight and to a cooler location to prolong the bloom period which can last up to one month.

When blooming is complete, the amaryllis plant is still growing. Remove the bloom stalk to prevent the bulb from expending energy on seed formation. Move the container back to the sunny window. When the danger of frost has passed you can begin to gradually expose the plant to the outdoors. First secure the container in an area outdoors with dappled shade. Over time you can move it to a location that receives six hours of full sun each day. Apply a balanced houseplant fertilizer monthly.

Prior to the first frost bring the amaryllis back inside and place it in a dark location. Stop watering it and when the leaves dry cut them off just above the bulb. Allow the bulb to rest for eight to twelve weeks with no water. When new growth appears or when you are ready to force the bloom, relocate the bulb to a sunny window and begin watering and fertilizing regularly. From dormancy to bloom it usually takes four to six weeks. Though amaryllis only require repotting every three to four years, the time to do this is after dormancy. (Cynthia Domenghini)


Figs in Kansas?

Yes, we can grow figs in Kansas. Not well, but we can grow them.

Most fig trees are only hardy to 12 to 15 degrees F though some are hardy down to 0 to 5 degrees F. Therefore, top growth often will not survive our winters. However, some varieties will re-sprout from the roots and produce a surprisingly large “shrub” by the fall. Since fruit is borne on new wood, Kansans can often enjoy a late harvest before cold weather shuts down growth.

Many figs are self-fruitful and will bear fruit without requiring a second variety. Others require cross-pollination and therefore you must have two different varieties in order to get fruit. Read the variety descriptions to determine whether you need two different varieties for fruiting.

Choose only the hardiest varieties. Chicago Hardy, Stella, Olympic and Peter’s Honey Fig were all recommended by Matt Bunch with “The Giving Grove” out of Kansas City. Florea is recommended for cold climates by One Green World. I chose Chicago Hardy and Florea for my garden.

The flowers of figs are borne inside the fruit and therefore not visible. Therefore, do not be concerned with the lack of visible flowers.

Chicago Hardy and Florea fruit turn purple at maturity though the color of mature fruit varies with variety. The fruit is quite mushy when ripe and will not keep well. If you produce more fruit than you can eat, consider drying as dried fruit can keep for six to eight months. (Ward Upham)


Trees Holding onto Leaves Longer than Usual

Have you noticed trees that typically drop their leaves in the fall are hanging onto their withered, brown leaves longer than usual? This year, once again, much of Kansas experienced a swift drop in temperature after warm fall weather. This has resulted in trees that have not hardened off and are now showing signs of marcescence.

Marcescence (mar-CESS-enss) is defined by leaves that wither but do not detach from the plant. When the temperature drops quickly, as we have experienced this fall, many trees didn’t have time to develop an abscission layer at the base of each leaf. The abscission layer is what separates the leaf from the tree and prompts it to fall to the ground. Although marcescence does not harm the tree on its own it may indicate damage has occurred to the tree.

The sharp drop in temperature may have caused damage to the phloem and cambium tissues beneath the bark. The phloem is responsible for carrying food throughout the tree, including to the roots, and the cambium produces new phloem. If these tissues are killed, the roots cannot receive food necessary for survival. Since the roots have some energy reserves available, the tree will not die immediately. Once the reserves are used up, death is imminent, typically the summer after the damage occurred. The xylem is the structure in the tree that carries water from the soil throughout the plant. Since it is not damaged in this process the tree will continue to receive water which will help maintain life until the roots run out of reserves.

Another complication that can arise from marcescence is if we experience a heavy snow or ice storm. The weight of snow and ice that can accumulate on the leaves along with windy conditions can cause branches to break.

If you are seeing trees with marcescence nothing needs to be done now except prevent further stress. Trees should enter winter with moist soil. Without knowing the extent of the damage to the tree tissue it is impossible to know what the end result will be. If only a small portion of the tissue was killed the tree may still recover. (Cynthia Domenghini)


Cynthia Domenghini, Instructor and Horticulture Extension Specialist

Ward Upham, Extension Associate

Department of Horticulture and Natural Resources

1712 Claflin, 2021 Throckmorton

Manhattan, KS 66506

(785) 532-6173

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