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Hartmann's Plant Company


Bunch of blackberries hanging from the plant


Black Raspberries, also known as Black Caps, are native to North America and can be found in many forested areas, open fields, along fencerows, and cultivated on farms and in gardens. They are grown commercially as far away as Korea. But the fruit has captured the creativity of others besides simply growing them for eating. Interestingly, for many years, the juice of the black raspberry was used to stamp meat with the USDA symbol of approval.  But their main attraction is their fantastic flavor, especially fresh from the bush or, failing that, in a frozen packet. A powdered form can be found in health food stores.

The plants are very easy to establish and will grow in virtually any soil type with little care.  The varieties that are grown by Hartmann’s Plant Company are Jewell, Pequot Lakes; and the only successful ever-bearing variety—Ohio’s Treasure.   We have chosen to grow these varieties for their fine flavor and high yields.  They have a small seed and are in season through the month of July in most places.

Black raspberries are seldom found in the fruit displays in grocery stores because of the shorter shelf life of the delicate and juicy berries.  Anyone who has had the opportunity to experience the taste of our black raspberries would prefer to eat one of them before eating a red raspberry because the sweetness and smooth texture of the fruits are simply sensational. They literally melt in your mouth, unlike any other fruit.

Beyond their incomparable taste, there are numerous health benefits to be derived from eating black raspberries. According to the Oregon Raspberry and Blackberry Commission: “Recent testing has confirmed that black raspberries have astonishingly high antioxidant levels. Antioxidant levels, shown in terms of their oxygen radical absorption capacity (ORAC), are a measure of a substance’s ability to absorb oxygen free radicals. Oxygen free radicals can damage DNA, cause cellular change, oxidize LDL cholesterol, and cause premature mental aging. Consuming foods high in antioxidants helps prevent cancer, heart disease, stroke, and possibly Alzheimer’s Disease. When compared to other foods, black raspberries have extremely high ORAC values. They are also among the highest foods in anthocyanins. Anthocyanins give foods like black raspberries their deep, dark color and have been shown to have anti-inflammatory and vasoprotective properties. Research has linked anthocyanins with improved vision, cardiovascular health, memory retention in old age and reduced risk of hypertension.” Research has shown the efficacy of black raspberries in the treatment and prevention of Barrett’s esophagus, a condition brought on by GERD (acid reflux), that can lead to esophageal cancer.

Black raspberries and freeze dried black raspberry powder blended with soy milk or blueberries can fortify resistance to several diseases and provide a refreshing drink or healthy lunch/snack substitute. In sum, there are many reasons for you to grow these black gems, just 1 plant will yield 4 pounds of nutritious fruits!

Pruning Kiwis In Summer

If kiwi vines are not pruned one or more times during the summer, the vines will become a tangled mess and your fruit production reduced in the current and following season.
There are several critical reasons for pruning vines during the summer:

  1. Pruning prevents the unruly vines from twisting around one another.
  2. Excess foliage will shade the flower buds, causing delayed flowering and poor pollination.
  3. Excess foliage will promote fungal growth because the flowers and fruit cannot dry after humid conditions, such as dew or rain.
  4. Insect pressure will increase because insecticides will not be evenly distributed throughout the dense foliage.
  5. The foliage and stem growth will delay timely and uniform fruit ripening.
  6. On the positive side, fruit size will increase with the removal of excess foliage and emerging stems.
  7. Fruiting wood must be selected for next year’s crop.

The first pruning of the vines should ideally occur when flower buds appear or at 5% open flower.


It is best to begin the pruning from the top of the plant and work the pruning downward. Support wires will vary in height and trellis style. This is the grower’s choice. Our top wire is 5’ above the ground. The bottom wire is 30” above the ground. There will be long and vigorous stem growth from the top cordon, especially on the male vines.

New stems grow vigorously, even wildly, and will become overgrown and out of control on the cordon within a few weeks, if the stems are not trimmed.


Summer is the time to prune out overly vigorous stems. When pruning the stems, be sure to select stems that must be kept on the cordon as fruiting stems for next year crop.

Fruiting stems should be spaced on the cordon 6”-8” apart. Stems will grow horizontally and vertically from the cordon. Select the fruiting stems and prune them back to approximately 8”-18” in length.

Select the fruiting laterals/stems. They may be growing horizontally or vertically. Again, prune them back 8”-18” in length.

After trimming away fruiting and unwanted stems of the cordon on the top wire, observe the growth on the trunk and at the plant base. Remove all growth in these areas.

When the pruning is complete the appearance of the Kiwi vines will be compact and the flowers and fruit will be exposed to the light and pollinating insects.

After 3-6 weeks into the summer months, more stems will grow on the cordon, previously pruned stems, and the trunk. Repeat the previous trimming steps to control growth and to create new fruiting laterals/stems for fruiting in the next year.

Imagine yourself as a kind of surgeon and give the vines a good, but thoughtful trimming, cognizant of the different parts of the plant’s anatomy: the trunk, cordons, fruiting laterals and new laterals selected for fruiting the following year. With practice, you will become an expert kiwi surgeon and your “patients” will thank you for the operation. You can even show off your work for others to admire.

Kiwi From The Vine

Last October, I was in my garden, enjoying the sweet flavors of the berries from my Kiwi vines. The vines were loaded with fruit even after surviving another cold winter, with temperatures exceeding twenty degrees below zero. The variety Issai surprised me; the vines yielded a full crop of fruit. This cultivar should be recommended for hardiness USDA zone 7 and 8, even though the hardiness zone for Issai is officially zone 5.

I have a variety of nine female cultivars planted along with four males. The only female cultivar that produced no yield was Cordifolia because of the cold winter temperatures. So I would suggest that this cultivar be grown in the warmer climate of USDA zones 6 -9.

Each cultivar has its own distinct flavor. I enjoyed popping the fig-like fruits in my mouth as I picked them fresh from the vines. If one is a Kiwi lover, there is nothing better than eating a vine-ripe Kiwi berry without needing to peel the fuzzy skin of the large type one finds in grocery stores. Kiwis have a long shelf life. Like, green bananas, Kiwi ripen up even more after sitting in a dish a few days. If you cannot eat all the fruit your vines produce, the berries can be stored in your refrigerator up to two weeks or frozen for delicious deserts during the winter.


Now that spring is here over most parts of the US, it is time to prune the vines. There are three parts to a Kiwi vine: a TRUNK, CORDON, and FRUITING laterals. See the photos below. The trunk grows from the roots up to the top horizontal wire. The arm-like cordon are supported by horizontal wires three to five feet high. The fruiting laterals grow from the cordon. Remove all growth at the base near the trunk. Remove all growth between the soil-line up to the cordon.

After finishing the pruning, take a look at the growth on the cordons.

1. Remove old fruiting laterals that produced fruit the previous summer.

2. Next step, observe last year’s new growth. These young fruiting laterals should have fruit buds if the plants were properly pruned the previous summer.

3. Many new laterals will have emerged from the cordon. Choose to grow these fruiting laterals every 6 to 8 inches apart along and on each side of the cordon.

4. Remove all other potential fruiting laterals from the cordon.

5. The fruiting laterals that are selected to produce new fruits should be pruned back to a length of 6 to 18 inches. The length is determined by the point where fruit buds do not appear on the lateral.

Be prepared for the next pruning in the summer. It will be easier to do. Summer pruning will be taught in the June Newsletter. For now, just wait for the flowers to bloom and the wind and insects combine to pollinate the delicate bell-like flowers.

If you do not have any of these delicious kiwi plants, the plants can be planted anytime from now until October.