Bucks County Herald

Elizabeth Ludlow Bowman: Tips for the Compleat Gardener

Two parents for a gymnosporangium

Cedar apple rust is the bloom of gymnosporangium juniper-virginianae.

Yesterday there was torrential rain, two inches in my domain, and this morning I came upon cedar apple rust, looking like orange, gelatinous aliens in the red cedars growing on the field’s edge and here is the photograph.

I have occasionally noted them in previous spring wood walks but they seem to be gone quickly but now I know that the fungus called gymnosporangium juniper-virginianae has spores on those orange horns. The fungus flings off into the wind to travel a mile or more in search of an apple tree where it lands on leaf or twig and can be embedded and infecting in four hours.

Cedar apple rust is the bloom of the aforementioned fungus and it is disfiguring to both trees. On the apple or crabapple the spore comes in the wind from the cedar, first making a pale yellow spot, which turns bright yellow then orange while spores form in tubular appendages around the hole in the leaf in which they are matured before being flung into the wind returning to the cedars in late July and August.

When the spore from the apple gets to the cedar it makes little nodules in the intersection of needles and waits a year before being able to sprout translucent, orange horns to fling spores on the wind.

The continued existence of G. juniper-virginianae depends on the presence of both hosts so one preventive is to keep all cedars and junipers at least a mile away from the apple orchards. The problem with this is that junipers and red cedars are always the first pioneers in a fallow field and the removal in a mile radius would be impossible. Fungicide is used in the apple orchards or resistant hybrids can be planted. I am not a fan of anything that ends in “-ide” though I am not speaking as an apple farmer.

I wonder what benefit each tree gains from this long distance exchange, there must be more to the story but I know it not. Juniper is a native tree and though apples are not native crabapples are and they have developed this relationship.

I have not heard there is food for some other creature involved but maybe it is all about the survival of the fungus. Anybody know?

Speaking of Virginia this is a good time to dig up roots of Virginia bluebells before they disappear completely.

The roots are usually red-brown and brittle but will sprout from pieces. I use a garden fork to loosen the nearby soil then dig with a trowel. Put the roots in a cardboard box. Cover with a layer of soil and keep slightly moist until planting.

Prune flowering shrubs right after they finish blooming, before they set buds for next season’s bloom. Feed them. Transplant until late June then wait until fall before moving. You can cut back tulip foliage that is browning. If the tulip failed to bloom or was pitiful dig the bulbs up and put them in the compost, vowing to buy more in autumn. A tulip planted in harsh, rocky soil can stay good for years and years but those planted in prepared gardens tend to split and become disappointing, dig them out.

Plant Easter flowers and lilies, they will usually come back unless you have let them dry completely out. You can plant annuals and non-hardy tubers such as dahlias and cannas now.

Mulch with compost, mushroom soil or nutripeat now because they feed the garden whereas bark mulch does nothing positive and even leeches away nitrogen and encourages the development of ugly mulch fungi.

Enjoy the moment.




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