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Messages - kumin

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Cold Hardy Citrus / Re: F2 citrange winter hardiness trial
« on: August 27, 2019, 10:43:43 AM »
This is the same tree last year. The fruit ripens every year, but not before October.

Cold Hardy Citrus / Re: F2 citrange winter hardiness trial
« on: August 27, 2019, 08:02:26 AM »
January low temperatures had no impact on the fruitfulness of Poncirus. This tree is full of fruit as usual.

I would separate cold hardiness from vigor. Vigor is displayed by rate of growth as well as duration of growth expressed by number of flushes and growth per flush. Cold hardiness consists of a number of factors: A. early initiation and retention of full dormancy, B. actual tissue resistance to freezing and freeze damage. I don't see vigor as being preventative of cold damage, and may be the opposite by exposing late, immature, succulent growth to freeze damage.

Recovery from freeze damage is a different matter, and vigor may indeed assist in repairing and overcoming winter damage. Therefore I would separate resistance to cold injury from subsequent spring recovery.

Vigor is desirable, but needs to by curtailed in the latter part of the season in order to allow the plants to achieve early and sustained dormancy in preparation for winter. A major difference between zone 6b Citrus and warmer areas is that achieving and maintaining dormancy is easier in the colder climates. The bottom line is whether the 6b plants can endure the cold under full dormancy.

An other factor is the plants ability, or lack thereof, to re-establish vigorous growth in the spring in cold wet soils after winter. Some plants appear to be stunted and slow in recovery.

In regards to Poncirus vs. it's hybrids, there are hybrid plants that are genetically more vigorous, as well as many that are stunted especially in the F2 generation. I find vigorous Poncirus hybrids to easily outpace pure Poncirus in growth. This may be a contributing factor in the greater hardiness of pure Poncirus.

Of the 69 survivors (with partial intact stem) out of 3,000 zygotic F2 citranges on trial, the tendency was for mid-range to dwarfish plants to predominate. None of the very most vigorous plants were survivors, these tended to continue growing too late in the season.

I am not a grower of pure Citrus species or cultivars and can't really comment on their vigor.

Cold Hardy Citrus / Re: Yuzu Seedlings
« on: August 08, 2019, 12:40:13 PM »
Millet, Bomand, your opinion. You are US-Americans. That obviously makes a difference. And you don't know much About Japan or Europe, I guess. Have a look at

Culinary tastes and preferences can and do change over time. Many of my favorite dishes were never tasted by my grandparents. Part of the experience can be enhanced by having the food prepared by someone familiar with and knowledgeable about the ingredients. I grew up eating foods I never eat today, due to overexposure and now strongly dislike them. I love some of the local foods and dislike others.

Cold Hardy Citrus / Re: Cuttings not rooting
« on: August 03, 2019, 12:46:35 PM »
Although foliage increases the transpiration rate and adds stress, a small amount of leaf surface can increase the stems attempt to generate root tissue. When a stem has neither roots nor leaves, stored reserves are needed to get the process going. I suspect a bit of leaf surface would make the cutting both more vulnerable to desiccation and more likely to initiate roots.

This is assuming there are no leaves on your cuttings. If the cuttings have leaves, my comments have no merit.

Cold Hardy Citrus / Re: Grafting
« on: August 02, 2019, 10:18:08 PM »
Brian, it helps to clear a 4-5" section of stem free of thorns, leaves, lateral branches, etc. Also, leaving a section of the leaf petiole attached to the bud can be used as a handle. This handle can remain on the bud and will indicate the health of the bud union. Green or yellow are good indications, black and brown often indicate failure.

The thought process that went into this graft/budding process is that a flap of bark loosened from the stem will heal back to the stem if immediately securely fastened to the stem. By inserting a thin scion with the cambium exposed on both sides, it will also be included in the healing tissues. When I initially started Citrus breeding decades ago, it was my only method of graftage.

Cold Hardy Citrus / Re: Grafting
« on: August 02, 2019, 07:25:08 AM »
I have success with a bark flap graft when the bark is slipping. These are done under active growing conditions and heals quite rapidly.
The process combines elements of budding and grafting. It's success is likely due to extensive cambium contact on both surfaces of the small diameter scion. I find Citrus as easy to graft as the pome fruits, certainly easier than persimmon.

Cold Hardy Citrus / Re: Flying Dragon Seedlings
« on: July 30, 2019, 06:44:55 PM »
Will2358, "rootstock" is a term used in the process of grafting. In grafting 2 or more plant parts in the creation of a grafted plant, rootstock refers to the lowest part of such a plant. It constitutes of the roots and the lower stem up to the point of meeting the scion, or interstem in a 3-part graft. In the process of grafting, the upper parts of the plant serving as the rootstock are sacrificed and removed. The scion portion of the completed graft determines most of the fruit characteristics, although the rootstock has a impact on hardiness, brix content, ripening, and other qualities influencing the fruit.

A plant  technically becomes a rootstock only when used for grafting purposes.

Cold Hardy Citrus / Re: Pruning Poncirus for root stocks
« on: July 26, 2019, 04:18:02 PM »
Walt, I suggest for rootstock purposes, to attempt to get a straight section of trunk with as few crooks as possible. If a rootstock is very crooked and contorted I cut the stem off directly above a vigorous sucker on the lower trunk.
I am attaching a photo of a plant that was branched and crooked this spring. I cut it off above a vigorous shoot in spring and it developed a nice straight stem.

I would prune any Poncirus destined for fruiting very minimally especially in regards to topping the trees.

Cold Hardy Citrus / Re: Winter twig die back.
« on: July 26, 2019, 04:03:54 PM »
Walt, are you finding the dieback in the most vigorous seedlings? I saw considerable dieback due to winter cold on the most vigorous, succulent shoots. A few trees haven't made new growth past last winter's dieback at this point.

Citrus General Discussion / Re: "Perfect" citrus fertilizer.
« on: July 26, 2019, 12:30:38 PM »
Soils vary greatly in available nutrients, therefore many growers will run soil tests to determine the baseline nutritional profile. Another factor is the seasonal nutritional needs for the plants/crop being considered. There is little point in overfeeding a nutrient that's in adequate or excess availability. Once the deficient nutrients have been identified, seasonal maintenance becomes important. Nutrients lost to leaching, adsorption by plants, etc. need to be replaced for optimal growth.

Cold Hardy Citrus / Re: F2 citrange winter hardiness trial
« on: July 24, 2019, 07:43:41 AM »
Mikkel, I don't have backups for all the survivors at this point. I have multiple backups for the best survivors. My intention is to have a lot of flowers blooming for open cross-pollination as well as controlled pollination. The protection I reference is planting in ground, but within a structure that can be covered and insulated against record low temperatures. I find that nutritional needs are met more naturally in open soil. However, I want to maintain some control over extreme temperatures and precipitation. I selected the best drained location on the property and will begin planting very shortly, so the roots can establish before winter.

The trees won't be protected until December so the cold will remain steady until spring. In the event that there's an unusually warm period in the winter, the heat must be vented outdoors. The intent is not to provide warmth during winter, rather to protect during sub-zero temperatures.

In regards to soil fertility, this region of Pennsylvania has soils that range from mediocre to very fertile, with the limestone soils being especially fertile. The greatest challenge on my property is drainage, rather than fertility, due to the clay content in the soil.

Cold Hardy Citrus / Re: F2 citrange winter hardiness trial
« on: July 23, 2019, 02:20:17 PM »
Here are some photos from today showing the Segentrange survivors before being planted into the soil in preparation for winter. These will be slightly protected in mid-December to mid-March.

These are the hardiest survivors, many which are making good growth through the summer.

This plant is a monofoliate Segentrange sibling to the rest of the plants. The spines are very slender and rather long. Conestoga # 058

# 010 Segentrange, one of the hardier, deciduous plants.

#002 Segentrange, an evergreen Segentrange showing good hardiness. This plant is not particularly thorny.

A TaiTri seedling making vigorous growth, having been planted from seed in late winter of 2019.

A Citrumelo also having been grown from seed in late winter of 2019.

Cold Hardy Citrus / Re: C35 Citrange
« on: July 21, 2019, 02:09:21 PM »
C-35 hardiness is contingent upon it's state of dormancy. It's hardiness is best under steady cold conditions.

Cold Hardy Citrus / Re: Lucky Day
« on: July 19, 2019, 03:12:34 PM »
This year's growth trunk suckers from a low position might be the easiest to root. The growth should be mature enough so it doesn't desiccate. Rooting hormone is helpful. The base of the cutting has the greatest rooting potential. Old mature growth from high positions will be much less likely to root. If cuttings wilt, the likelihood of rooting is diminished.

If the internodes are long enough it's possible to get one graft per bud from the scionwood.

Citrus General Discussion / Re: Small diameter scion Citrus graft
« on: July 13, 2019, 06:02:02 PM »
2 examples of buds emerging as the bark flap grafts are progressing. Practically all the grafts are alive at this point, and will hopefully emerge, providing the buds on the scions are mature enough.

Citrus General Discussion / Re: Small diameter scion Citrus graft
« on: July 11, 2019, 09:00:21 PM »
Despite similarities, this graft doesn't cut into the underlying wood on either the scion or the rootstock, except for the very end point of the scion.. The objective is to have cambium touching cambium on both sides of the scion. The length of the epidermis removed is the same on both sides of the scion. For best results when forcing the buds, it's important that the scion buds aren't too immature.

Citrus General Discussion / Re: Butterflies...
« on: July 05, 2019, 08:26:54 PM »
SLF has been found in Winchester, VA northwest of Washington D.C. which is southwest of the initial discovery site in PA.

Citrus General Discussion / Re: Butterflies...
« on: July 05, 2019, 04:27:36 PM »
The Spotted Lanternfly are already entering the 4th instar red nymph stage. The next stage is flying adults. The first local adults arrived in October, 2018. At this point they appear unstoppable.

Citrus General Discussion / Re: Butterflies...
« on: July 02, 2019, 12:11:46 PM »
Spotted Lanternfly in feeding location on stem, but in resting posture. This is likely the last black/white coloration, the next instar should be red/white spotted.
This one is perched on a citrange. Hopefully they don't have an affinity for Citrus. The early nymph stages are less discerning as to plant host, with the later stages becoming increasingly selective. The infested area is increasing each year, autumn migration preceding egg-laying being one mode of spreading, along with egg masses getting hitchhike rides on vehicles over winter. The females lay eggs on any materials, not only trees.

Citrus General Discussion / Re: Butterflies...
« on: July 02, 2019, 05:49:12 AM »
Brian, despite making a number of online searches, I haven't been able to determine that Citrus is a host of SLF. As I also reside in the affected area, I have been keeping a close eye on the nymphs this spring. To this point, although there are incidental SLFs on the Citrus, I am uncertain that they're feeding on Citrus.
Pecan, nightshade, apple, grapes, and especially tree of heaven are magnets for SLF.

Citrus General Discussion / Re: Small diameter scion Citrus graft
« on: June 29, 2019, 05:45:11 PM »
Kelley_GA8a, to more fully answer your question regarding wrapping the graft: If the humidity is low and it's hot and windy, I will run parafilm up and down the graft to cover the entire graft area. Presently, humidity is high and I allow the small leaflets to remain unwrapped. It's all a matter of keeping an eye on the leaflets and avoiding desiccation. Additional wrap can be added or removed as required. Leaflets turning black, or drying up is not a good sign.

Cold Hardy Citrus / Re: Unknown citrus
« on: June 29, 2019, 03:57:09 PM »
Poncirus hybrid, surviving rootstock?

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