Hi,

I just moved to Redwood City, California, and there is a walnut tree on the
property with green walnuts. How can I tell the difference between English
walnuts and black walnuts in terms of the green fruit (now on the tree) or
the leaves, etc.?

Thank you very much.

Claire Gilbert

Claire W. Gilbert said:

I just moved to Redwood City, California, and there is a walnut tree on the
property with green walnuts. How can I tell the difference between English
walnuts and black walnuts in terms of the green fruit (now on the tree) or
the leaves, etc.?

Common [English]: walnut 5-7 leaflets, terminal leaflet large, leaflet margins smooth
edged, leaves are aromatic when crushed. Nuts vary greatly in size and shape but
typically have shallow fissures and the shells are light coloured. The bark is smooth
when young and grey in colour, only becoming fissured after about 15 years.

Black walnut: 9-17 leaflets, terminal leaflet small or absent, leaflet margins finely
serrated, leaves are not aromatic when crushed. [picture] In addition the midrib
underside the leaf is covered with fine hair. Leaflets tend to angle down from the
midrib. Nuts vary greatly in size and shape but typically have deep fissures and the
shells are dark coloured. The bark is ridged from a young age.

Hybrid walnut: 7-12 leaflets, terminal leaflet quite large, leaflet margins coarsely
serrated, leaves are not aromatic when crushed. The midrib underside the leaf is
hairless. Leaflets do not angle down from the midrib. Nuts vary greatly in size and
shape but typically have deep fissures and the shells are dark coloured. The husks
are green, lightly textured and very aromatic. The bark is ridged from a young age.

(courtesy http://www.walnuttrees.co.uk/FAQ.htm#species_look)

BTW, 'English' walnuts produce much less juglone than black walnuts -- but are
sometimes grafted onto black walnut or hybrid rootstock, which would make them
far more likely to cause walnut wilt in suceptible plants than purely English walnuts.


--
Pat in Plymouth MI

Any technology distinguishable from magic is insufficiently advanced.
(attributed to Don Marti)