Blog Posts - K-State Horticulture Newsletter

Prop Up Fruit Tree Limbs if Needed

7/19/2021

Heavy fruit loads this season may cause limbs to break if they are not given extra support. As fruits increase in size, the additional weight on individual branches may be substantial. One-inch thick boards that are 4 inches wide can be used to prop up limbs. You may wish to use two boards that overlap so the amount they overlap can be adjusted to change the total length of the board. Two to three screws can hold the two boards together. Cut a "V" on the top edge of the board on which the limb will rest so that it doesn't slip off. Long limbs that are heavily loaded with fruit may need a prop in the center and another to support the outer part of the limb.

A plastic belt-like material that is about 2 inches wide may also be used. This can be tied to a heavily loaded limb, then to a large diameter limb above for support. Where a large limb is used for support, it is good to have it supporting limbs on opposite sides so the weight is balanced.

Another solution is to wrap a tape or belt material around the tree in a spiral to prevent limbs from bending until they break. Heavy twine may be used, but it should be removed when the fruit is picked or soon after so it does not cut into the bark on the limb.

Check trees regularly, up to two times a week during the last month the fruit are maturing. You will find additional limbs that need support. Tending to the heavily loaded tree limbs will reduce the number of broken limbs and help keep a balance of the fruiting wood in your tree. Next year, prune long, weak branches back to a side branch to help prevent this problem. (Ward Upham)

Dividing Iris

7/19/2021

Bearded irises are well adapted to Kansas and multiply quickly. After several years, the centers of the clumps tend to lose vigor, and flowering occurs toward the outside. Dividing iris every three to five years will help rejuvenate the planting and increase flowering.

Iris may be divided from late July through August, but late July through early August is ideal.
Because iris clumps are fairly shallow, it is easy to dig up the entire clump. The root system of the plant consists of thick rhizomes and smaller feeder roots. Use a sharp knife to cut the rhizomes apart so each division consists of a fan of leaves and a section of rhizome. The best divisions are made from a double fan that consists of two small rhizomes attached to a larger one, which forms a Y-shaped division. Each of these small rhizomes has a fan of leaves. The rhizomes that do not split produce single fans. The double fans are preferred because they produce more flowers the first year after planting. Single fans take a year to build up strength.

Rhizomes that show signs of damage due to iris borers or soft rot may be discarded, but you may want to physically remove borers from rhizomes and replant if the damage is not severe. It is possible to treat mild cases of soft rot by scraping out the affected tissue, allowing it to dry in the sun and dipping it in a 10 percent solution of household bleach. Make the bleach solution by mixing one-part bleach with nine parts water. Rinse the treated rhizomes with water and allow them to dry before replanting.

Cut the leaves back by two-thirds before replanting. Prepare the soil by removing weeds and fertilizing. Fertilize according to soil test recommendations or by applying a complete fertilizer, such as a 10-10-10, at the rate of 1 pound per 100 square feet. Mix the fertilizer into the soil to a depth of 6 inches. Be wary of using a complete fertilizer in areas that have been fertilized heavily in the past. A growing number of soil tests show high levels of phosphorus. In such cases, use a fertilizer that has a much higher first number (nitrogen) than second (phosphorus). (Ward Upham)

Peonies with the "Measles" and Powdery Mildew

7/19/2021

This is the time of year that peonies show symptoms of "measles" and/or powdery mildew.

Measles: Measles is a disease, also known as red spot, that causes distinct, reddish-purple spots on the upper leaf surfaces. These spots often coalesce and become large, reddish purple blotches on the upper leaf surfaces but are a light brown color when viewed from the underside of the leaves. The spots on stems will merge and form streaks that are reddish brown.

Powdery Mildew: Plants infected with powdery mildew look like they have been dusted with flour and can lead to death of the leaves. This disease isn’t as common in Kansas than Measles but does show up at times.

Sanitation is the best control for both these diseases. Remove all diseased tissue, including stems, at the end of the growing season. Actually, all foliage can be removed in mid-August with no harm to the plants as the plants will be essentially dormant. Foliage that has already died should be removed now.

Mulch that contains plant debris should also be discarded and then replaced with fresh mulch. Reducing the source of the inoculum will reduce the chances of another severe outbreak next year. (Ward Upham)

When to Pick Tomatoes

7/12/2021

Tomato Cracking

7/12/2021

Tomatoes often have problems with cracking caused by pressure inside the fruit that is more than the skin can handle. Cracks are usually on the upper part of the fruit and can be concentric (in concentric circles around the stem) or radial (radiating downward from the stem). We don’t know everything about cracking but here is what we do know.

Tomatoes have a root system that is very dense and fibrous and is quite efficient in picking up water. Unfortunately, the root system can become unbalanced with the top of the plant. Early in the season it may be small in relation to the top growth resulting in blossom-end rot when the weather turns hot and dry. Later it may be so efficient that it provides too much water when we get rain or irrigate heavily after a dry spell. This quick influx of water can cause the tomato fruit to crack. Therefore, even, consistent watering can help with cracking. Mulching will also help because it moderates moisture levels in the soil. However, you can do everything right and still have problems with cracking in some years.

We have evaluated varieties for cracking during our tomato trials at K-State. It takes several years worth of data to get a good feel for crack-resistant varieties but we have found some real differences. Some varieties crack under about any condition and others are much more resistant. The difference seems to be pliability of skin rather than thickness — the more pliable the skin the more resistance to cracking.

The old variety Jet Star has been the most crack resistant of any we have tested including the newer types. Unfortunately, Jet Star is an indeterminate variety that puts out rampant growth.
Newer varieties with more controlled growth are often more attractive to gardeners. Mountain Spring, Mountain Pride, Mountain Fresh, Floralina and Sun Leaper are smaller-vined types that have shown good resistance to cracking. (Ward Upham)

How to Pick a Ripe Melon

7/12/2021

Telling when a melon is ready to be harvested can be a challenge, or it may be quite easy. It all depends on the type of melon. Let’s start with the easy one. Muskmelons are one of those crops that tell you when they are ready to be picked. This can be of help to not only harvest melons at the correct time but also choose good melons when shopping. As a melon ripens, a layer of cells around the stem softens so the melon detaches easily from the vine. This is called “slipping” and will leave a dish-shaped scar at the point of stem attachment. When harvesting melons, put a little pressure where the vine attaches to the fruit. If ripe, it will release or “slip.”

When choosing a melon from those that have already been harvested, look for a clean, dish-shaped scar. Also, ripe melons have a pleasant, musky aroma if the melons are at room temperature (not refrigerated).

Watermelons can be more difficult and growers often use several techniques to tell when to harvest.

1. Look for the tendril that attaches at the same point as the melon to dry and turn brown. On some varieties this will need to be completely dried before the watermelon is ripe. On others it will only need to be in the process of turning brown.

2. The surface of a ripening melon develops a surface roughness (sometimes called “sugar bumps”) near the base of the fruit.

3. Ripe watermelons normally develop a yellow color on the “ground spot” when ripe. This is the area of the melon that contacts the ground.

Honeydew melons are the most difficult to tell when they are ripe because they do not “slip” like muskmelons. Actually, there is one variety that does slip called Earlidew, but it is the exception to the rule. Ripe honeydew melons become soft on the flower end of the fruit. The “flower end” is the end opposite where the stem attaches. Also, honeydews should change to a light or yellowish color when ripe, but this varies with variety. (Ward Upham)

Netting Grapes

7/12/2021

If you have grown grapes before, you have likely discovered that birds like grapes as much as you do. There are two methods homeowners can use to protect the fruit. The first is bagging where a paper bag is placed over the cluster and secured with a twist tie or staple. The bag can be left until it is time for harvest as flavor and color are determined by sunlight hitting the leaves rather than the cluster.

The second method is to net the crop. The most common and least expensive netting is the lightweight, black, polypropylene type with a square mesh size of ½" x ½”. This can be difficult to install and remove as it tends to stick to itself and to the vines. However, it is effective. Woven mesh bird netting is also effective and easier to work with but is more expensive.

If your trellis has a wire at six feet high, purchase a net that is at least 14 feet wide so that it can be draped over the grapes and secured along the bottom edge with clothes pins. Nets that are 17 feet wide are less common but give more material to work with and are therefore easier to secure. (Ward Upham)

Green June Beetle

7/12/2021

These large beetles feed on sweet corn, blackberries, and peaches. They look much like the common May beetle, or June bug, but have a dull, velvety green color. The underside is more of an iridescent green. These beetles have poor navigational skills and seem to fly until they hit something. They also make a buzzing sound somewhat like a bumblebee. Unfortunately, they are also about the size of a bumblebee and so cause concern for many gardeners even though they cannot harm people. As noted above, they may damage crops.

A number of general-use insecticides, including acetamiprid (Ortho Flower, Fruit & Vegetable Insect Killer), carbaryl (Sevin dust) and malathion, may be used to discourage feeding. See table below for what can be used and the number of days between application and harvest.â€‹

Insecticide	Peaches	Blackberries, raspberries	Sweet Corn
Carbaryl	3*	7	2
Malathion	7	1	--------
Acetamiprid	7	1	-------

* Days to Harvest

Carbaryl has a two-day waiting period between spraying and harvest on sweet corn and a three-day waiting period on peaches. There is a seven-day waiting period for Sevin on blackberries, so malathion, with a one-day waiting period, may be a better choice. Acetamiprid has a 7 day waiting period on peaches and a 1 day waiting period on blackberries and raspberries. It appears the Ortho product with acetamiprid has been discontinued but there still may be some existing stock. (Ward Upham)

Raspberries and Blackberries After Harvest

7/12/2021

Raspberries and blackberries are perennial plants with biennial canes. What that means is that though the plants live year after year, each individual cane only lives two years. Most commonly the first year canes, referred to as primocanes, grow but don’t fruit. Primocanes become floricanes the second year. Floricanes fruit and then die.

So what do you do with these dead canes when they die after fruiting? Though many gardeners leave the canes for removal the following spring, it is best to remove them immediately after they die if your plants have had problems with disease such as anthracnose (see photo). See https://ohioline.osu.edu/factsheet/plpath-fru-27 . Remove the canes as close to the ground as possible without damaging the primocanes. It is best to discard, burn or bury any infected canes. (Ward Upham)

Tan or White Drupelets on Blackberry and Raspberry Fruit

7/12/2021

Blackberry and raspberry fruit will often develop white or tan drupelets on the berry. Though we are not completely sure of the cause in all cases, two commonly given reasons are stinkbug damage and sunscald. Damage has been attributed to stinkbugs if the pattern of off color (not white) drupelets is random. Stinkbug damage is caused by the insect feeding on the blackberry receptacle and injuring drupelets on either side. Damaged drupelets are often scattered. Sunscald damage will be on the side of the fruit exposed to the sun and has several to many drupelets in an area being affected.

Neither condition affects the eating quality of the fruit unless the stink bug releases the “stink” with which it is associated rendering the fruit inedible. By the time damage is seen, it is too late for control. (Ward Upham)