In 1997, a small cutting (25 cm, 10 inches) of the Navajo willow tree (Salix matsudana) was planted in my garden in Belgium. Today, ‘my’ Navajo willow is almost 12 meter high.
Looking for simple methods to make reforestation projects in the drylands more successful (by limiting irrigation-repetition and enhancing survival rate of the trees in dry climatic conditions), I started growing willow cuttings in plastic bottles (container gardening). After cutting up a rather thin branch of the tree in small pieces (8-10 inches, 20-25 cm), I kept these fine cuttings in a glass of water until they were sufficiently rooted (which is occurring quite quickly with willow cuttings). Then I planted each of the cuttings in a plastic bottle filled with potting soil.
From here off, I let the cuttings develop a strong rootball in the bottle. Numerous absorbing roots are growing throughout the potting soil, which is easily kept moistened because evaporation is minimal (small bottleneck) and because at the bottom of the bottle a small quantity of water is stored, up to the level of the two perforations. From this small water reserve, all the water needed is sucked up by the potting soil staying permanently moistened. The only minimal volume of irrigation water that has to be added is the one that is transpired by the leaves.
It is my intention to plant these cuttings when a good number of roots reach the bottom of the bottle and start curling. At that moment I will cut off the bottom of the bottle at the level of the two perforations, i.e. at 1 inch or 2,5 cm from the bottom. Taking off that bottom cup of the bottle, I will set the lower part of the rootball free and a number of young roots will hang out off the bottle.
Now I will plant this young willow tree, bottle and all, in a plant pit, taking care of keeping the upper part of the bottleneck above the soil surface. The bottle, still containing the major part of the rootball, will be buried completely except for the top inch of it, popping out of the soil to allow once or twice additional watering. The bottom part of the rootball, which was hanging out of the bottle, will now be in direct contact with the soil of the plant pit. Minimal watering through the bottle will keep those bottom roots moistened, so that they will start growing into the soil. In the meanwhile, the rootball inside the bottle will be keeping the young willow plant growing.
At the end of the day, the young willow plant will be rooting deeper and deeper in the soil, so that watering will be less needed. The growing willow stem will finally break up the plastic bottle of which the small debris will sit for a longer time in the soil.
Knowing that with this ‘bottle reforestation’-method survival rate will be significantly higher, the advantages of booking a total success with this way of reforesting are more important than the fact of burying some plastic bottles here and there. Anyway, better to bury that plastic than to leave it littered in the environment.
REFORESTATION WITHOUT PLASTIC BOTTLES
In February 2010, my good friend Marc PILLE took some Navajo willow cuttings home in Belgium and kept them simply in a plastic shopping bag with 2-3 inches (5-8 cm) of water for two weeks.
He observed that the bigger cuttings (a finger thick) were rooting much quicker than the thinner ones.
Then he took the cuttings to his projects in Mali (Sahel country, West Africa) and planted them directly in the dry soil of a nursery. He watered them from time to time to keep the soil moistened and to stimulate more rooting.
Within the first two weeks after planting in the hottest and driest period of the year, a number of cuttings started shooting already. This shows that the drought-resistant Navajo willow (Salix matsudana) could be a fantastic tree species to be used for reforestation in the drylands. These first results indicate that the Navajo willow can be an excellent tool to combat desertification.
My sincere thanks go to Marc PILLE for his valuable contribution.
REQUEST TO VISITORS OF THIS BLOG
Cuttings of Navajo Globe Willow (Salix matsudana ‘Navajo’)
As we are setting up tests with drought-resistant varieties of trees to be introduced in the drylands, we are looking for small cuttings (20-25 cm, 8-10 inches) of the Globe Navajo willow (Salix matsudana ‘Navajo’). We would be very grateful to receive some cuttings from different origins to compare drought tolerance.
‘Navajo’ is a very hardy tree, adapted to high desert climates, round-headed upright and fast-growing, spreading, large, deciduous, long lived tree, medium-sized, 20’ to 70′ tall and wide.
The tree seems to be sheared into a perfect ball. Its branching habit results in a characteristic globe shape: a broad, rounded, perfectly symmetrical crown spread of mostly fifty feet. Young 15’ tall trees start showing the rounded crown.
Slender leaves are bright green, lance-shaped, 2″-4″ long, turning yellow in fall.
Unlike most willows, this variety is popular in high desert and drylands because it is drought tolerant, adaptable to a wide range of soil conditions
The name of the ‘Navajo’ variety of the Globe Willow is probably synonym with ‘Umbraculifera’.
The Navajo Globe Willow is related to the Corkscrew willow (Salix matsudana ‘Tortuosa’). Cuttings of this Corkscrew Willow would also be welcome.
Please send some cuttings to:
Prof. Dr. Willem VAN COTTHEM
B 9080 ZAFFELARE (Belgium)