Winter Injury of Filberts at Geneva 1933-34[A]

Winter Injury of Filberts at Geneva 1933-34[A]

By G. L. Slate

New York Experiment Station, Geneva, N. Y.

Last year I reported to you the winter injury to the Geneva filbert collection resulting from a very mild winter. This year I am reporting the damage resulting from the coldest winter on record in western New York. Varieties that have withstood both winters may be considered sufficiently hardy for anything western New York and regions with a similar climate have to offer in climate.

A brief summary of the winter and its effects on other fruit plants in the vicinity of Geneva will serve as a background for the data on filberts. The first severe cold occurred on December 29 when the temperature dropped to -21° F. This equalled the previous low record established in February, 1896. On February 9 the minimum temperature recorded was -31° F. or ten degrees lower than anything previously recorded in the history of the Station. The minimum on February 8 was -16° F. and on February 10, -18° F.

Fruit trees suffered severe injury from these extreme temperatures. Nearly all the older Baldwin apple trees in the vicinity were killed or so severely injured as to be of no further value for fruit production. Peach fruit buds were all killed and many of the trees succumbed, even in well cared for orchards. Very few sweet cherry buds survived, and many trees were injured or killed. Delaware, Catawba and Niagara grapes were also killed to the ground or lost most of their buds. Japanese plums failed to bloom, and the trees were severely injured. Nearly all climbing roses were killed to the ground. Even the native elderberry, Sambucus canadensis, was killed back in many cases. Such was the winter experienced by the filberts.

Before classifying the filbert varieties as to their hardiness, some general statements regarding the effect of the cold on the filberts may be of interest.

The injury to the wood seemed to be due to a gradual drying out and the clear cut distinction between winter killed wood and live wood so evident in peaches, apples, and pears did not show in the filberts. The wood of the filberts had a dried out appearance with a few brown streaks so that one could not predict definitely in February the amount of injury. It was not until midsummer that a true picture of the injury to the wood could be obtained. This gradual drying out of the wood without the clear cut distinctions between dead and live wood also characterized the winter killing of the wood of grapes and raspberries. In the spring new growth on the injured filbert wood started late. If the injury was slight the foliage soon reached normal size. In some cases the early leaves were very small, but later attained normal size. With trees that were severely injured the leaves remained small until midsummer and then gradually turned yellow and died. Many branches were killed outright and failed to start or only a bud here and there would start. On the trees of a few varieties that were injured the least, a few small leaves were the chief evidence of winter injury.

The recuperative power of the filbert seems to be nearly as great as that of the peach and pear insofar as this may be determined by observation in the orchard. In spite of the past winter the station filbert orchards present a fairly good appearance except for a few varieties. It is probably safe to consider filberts as hardy as peaches and sweet cherries.

The flowers of the filbert show a greater range in hardiness than those of peaches and sweet cherries. The staminate flowers or catkins of a few varieties are definitely hardier than peach flowers. Not a single peach blossom survived but three filberts bloomed with only slightly more than the usual amount of catkin killing. The pistillate or female flowers are much hardier than peach flowers. The pistillate flowers are also hardier than the wood as flowers were observed on trees the wood of which was nearly dead by midsummer. In the older orchard about 16 varieties bore a number of pistillate flowers that were recorded as medium or greater. These did not all set nuts, however, owing to the scarcity of pollen, but the crop on seven varieties was about medium. It should be emphasized at this point that there were no peaches, practically no Japanese plums, very few sweet cherries, and very few grapes in the Station orchards and vineyards this year. Trees in the partially protected orchard fared somewhat better in regard to catkin injury than those in the more exposed orchard. That full exposure to the wind has much to do with winter killing of catkins is shown by the following. After the severe freeze of December 29 and 30 when -21° F. was experienced, catkins of several varieties were forced in the office. These all opened and shed pollen normally. January 29 and 30 near zero temperatures were experienced with very strong winds. Catkins forced in the office immediately after this were nearly all killed. Since zero temperatures are not uncommon at Geneva in winter, but are rare with strong winds, much of the injury may be attributed to the combination of wind and cold.

Young trees were injured less in wood than old trees. This is well shown by a comparison of two lots of Kentish Cob of different ages. Nine 9-year-old trees were killed back from 50 to 80 percent in addition to considerable weakening of the remaining wood. Eleven two-year-old trees in the same orchard were uninjured.

The importance of exposure to winds as a factor in causing catkin killing is further shown by a comparison of catkin killing in the two filbert orchards at Geneva. In the younger orchard which is exposed to the full sweep of the west wind not a catkin survived on any of the 66 varieties in that orchard. In the other older orchard which is protected on the west and north by buildings and spruce trees, sufficient catkins survived on three varieties to provide for proper pollination. In discussing the effects of winter injury on the different varieties it will be necessary to make a distinction between the two orchards. Orchard 6 is the partially protected planting while Orchard 16 is fully exposed. Most of the trees in Orchard 6 were nine years old, while those in Orchard 16 are six years old or less. Wood injury, catkin injury, and pistil injury will be treated separately.

In the first group are those varieties which suffered very severe wood injury. They are Clackamas, Early Globe, English Cluster, and Oregon. The latter two are very similar and may be identical. These were all nine year old trees located in Orchard 6. The trees were so severely injured that their recovery is doubtful and the development of new trees from suckers will be necessary. Clackamas evidently suffered root killing as only one of the six trees is producing suckers. In this group the trees leaved out, but the foliage was small, usually less than one-fifth the size of normal foliage, and growth weak. By August the leaves were yellow and many were shrivelling.

Varieties moderately to severely injured in Orchard 6 were Barcelona, Kentish Cob (Du Chilly), Fertile de Coutard, Minna, Purple Aveline, Red Aveline, White Aveline, White Lambert, D'Alger, and Montebello. In Orchard 16 the severely injured varieties were Garibaldi, Kentish Filbert, Marquis of Lorne, Princess Royal, Red Skinned, The Shah, Webbs Prize Cob, Bandnuss, Einzeltragende Kegelformige, Liegels Zellernuss, Multiflora, Schlesierin, Sicklers Zellernuss, Truchsess Zellernuss, Vollkugel, Volle Zellernuss, Romische Nuss, Kruse and Rush. The trees of varieties in this group were severely injured, but have a fair chance of recovering. In many cases from 50 to 90 percent of the top was killed outright, and new growth was weak. Most of the trees have a few fairly strong shoots from the trunk or larger branches from which a new top may be developed. Four out of 22 trees of Barcelona were killed entirely, indicating root as well as top killing.

The last group includes those varieties of which less than 20 percent of the wood was killed. The new growth was weakened slightly or not at all. In many cases the tree is apparently uninjured and occasionally a single tree of a variety may be severely injured while the others are unhurt. Varieties in Orchard 6 belonging in this group are Alpha, Buttner Zeller, Cosford, Daviana, Gubener Zeller, Gunzlebener Zeller, Gustav Zeller, Lange Landsberger, Fichtwerdersche Zeller, Noce Lunghe, Italian Red, Large Globe, Medium Long, Bollwiller, Nottingham, Halle, Red Lambert, Gasaway, Guebener Barcelloner, Blumberger Zeller, Bixby, Jones Nos. 83, 207, 269, 310, and Corylus colurna.

In Orchard 16 varieties in this group include Cannon Ball, Duke of Edinburgh, Pearson's Prolific, Barr's Zellernuss, Berger's Zellernuss, Beethe's Zellernuss, Eckige Barcelloner, Grosse Kugelnuss, Heynicks Zellernuss, Jeeves Samling, Kadetten Zellernuss, Kaiserin Eugenie, Kurzhullige Zellernuss, Longe von Downton, Ludolph's Zellernuss, Luisen's Zellernuss, Mogulnuss, Neue Riesennuss, Northamptonshire, Prolifique a coque serree, Imperial de Trebizond, and Russ. Native sorts in this group are Winkler, Littlepage, Wilder, a Corylus americana variety from the east end of Lake Ontario, and a Corylus rostrata from Rhode Island. Seventeen 3-year old French varieties were also uninjured, but in view of the general lack of wood killing, on young filberts, they are not included in this list. It is evident then that we have a number of varieties of which the wood is fairly hardy.

Catkin killing was very severe in both orchards and only those varieties which had a few live catkins are listed. In Orchard 6 the catkin killing on five trees of Italian Red ranged from 20 to 50 percent and on six trees of Red Lambert from 10 to 20 percent. A few catkins on Alpha also survived. The remaining 35 filbert varieties in this orchard lost all their catkins. Several Jones hybrids in this orchard fared somewhat better. A few catkins survived on Bixby. Jones 269 lost 10 percent, Jones 310 lost 30 percent, and Jones 207 lost none of its catkins. All the catkins were killed on Jones 83.

In Orchard 16, the story is soon told. Not a single live catkin was found in the spring on the 66 filbert varieties in this orchard. Of the native hazels Bush lost all its catkins, and Winkler none. All catkins were dead on the Corylus rostrata from Rhode Island.

As stated earlier, the pistillate flowers were hardier than the catkins and nearly all varieties in both orchards had at least an occasional female flower. However, only those in which the number of pistillate flowers was described as medium or numerous will be recorded here. In Orchard 6 these varieties were Alpha, Cosford, Fichtwerdersche, Gubener Zeller, Gunzlebener Zeller, Gustav's Zeller, Longe Landsberger, Noce Lunghe, Italian Red, Medium Long, Bollwiller, White Lambert, Gasaway, Gubener Barcelloner, Blumberger Zeller, and Unknown. Five Jones hybrids including Bixby had a full pistillate bloom. Due to wood injury and possibly to a scarcity of pollen only a few of these varieties bore more than a few nuts. Varieties bearing a medium crop are Cosford, Italian Red, Medium Long, Gubener Zeller, Gunzlebener Zeller, Bollwiller, and Unknown. Four of Jones hybrids including Bixby, are bearing fair crops. The other varieties in this orchard are bearing only an occasional nut or none.

In Orchard 16 the pistillate flowers were described as medium or numerous on the following varieties: Barr's Zellernuss and the Winkler hazel. The other 65 varieties bore only an occasional flower. No filbert pollen was available in this orchard, consequently Winkler is the only variety fruiting.

In Orchard 16 were 534 two-year-old trees from crosses between Rush and various filbert varieties. The cross was made by Mr. Reed and the seedlings were sent to Geneva by the late Mr. Bixby. Of these 534 seedlings, 62 bore catkins. The catkins on 14 of these were uninjured, 19 had varying amounts of injury, and 29 suffered 100 percent killing. Three hundred and ninety-two bore pistillate flowers and 74 of these would probably have had full crops had they been pollinated. In view of the complete loss of catkins on the filbert varieties in this orchard, the survival of catkins on about half of the blooming seedlings is of considerable interest to the filbert breeder. In addition, none of these hybrids experienced any wood killing.

If the list of varieties which passed through the very severe winter of 1933-34 is compared with the list of varieties which were not seriously injured by the very mild winter of 1932-33, only two sorts, Italian Red and Red Lambert are found to be satisfactorily hardy in wood and catkin. Red Lambert is too unproductive to be used except as a pollenizer. Italian Red may therefore be considered the most promising variety now available for western New York conditions. The nut is satisfactory and the tree is one of the most productive. Cosford and Medium Long may also be considered among the hardiest in spite of the complete loss of catkins last winter. In all previous winters they have been among the hardiest in wood and catkins. No variety should be eliminated because of a lack of hardiness during the coldest winter on record in the region where it is being grown, if it possesses other desirable characters.

I think considerable encouragement may be derived from the previous winter's experience. We are at last down to rock bottom and know what is hardy and what is not. It is evident from the behavior of the Jones hybrids and Mr. Reed's hybrids involving a similar parentage that sufficiently hardy varieties will result from this line of breeding work to make filbert culture possible in those sections of the country that are not too cold for peaches.