Nun Orchid Weekend

  

I've had my successes and failures with orchids.  I remember a time about 20 years ago when I had a small bedroom with a south-facing window in which I grew Phalaenopsis, some Cymbidium and a couple of Paphiopedalum.  The Phalaenopsis bloomed reliably in response to the cooler temperatures of fall and the brighter light that they got when the large red oak outside lost its leaves.  When children came, this became the nursery, and the orchids made way for two cribs.  One Cymbidium went to work with me where it bloomed nearly continuously.

My favorite orchid is now Phaius tankervilleae, the nun orchid.  I got mine for a mere $25 at a local nursery as an impulse sale about four years ago.  A friend told me that the key to blooming this species is to treat them just like amaryllis; grow them out on the deck in sun over the growing season and fertilize them generously, allow them to dry a bit in autumn and allow them to experience a bit of autumn chill.  This plant goes out on the deck in May where it is kept constantly moist and gets liquid fertilizer three or four times until I bring it indoors in late October.  Because it's native to swamps, it can be planted in regular potting soil and relishes constantly wet conditions.

I've had to divide it twice already.  It's not a slow grower at all.  It blooms reliably in March every year, and is at times fragrant. If you are looking for an easy and very rewarding orchid, I'd highly recommend this species.

Do I Like Iris 'Katherine Hodgkin'?

I shot this Iris 'Katherine Hodgkin' in the Boxwood Collection last week.  I've always admired pictures of her, but I've never grown it myself.  The piece of mulch in the picture tells you something about how tiny they are.  When I first noticed this clump from afar, I'll have to say I was not impressed.  As I got closer, my interest piqued and I ended up admiring the bold lines and spots in the falls that contrast with the blotch of yellow.  The little clump was part of an effort to add a longer season of interest to a planting of tree peonies we have near the small parking area in the Boxwood Collection.  Like all dwarf iris, it gets lost if there aren't enough of them planted in a space.  I suppose they would work nicely in a small garden or rockery, or perhaps even in pots.  I tend to be very attracted to flowers with bold stripes, striking color combinations, and spots, but what looks cool close up somehow didn't look great from afar.  I still don't know if I will end up planting some at home. 

Grafting

Today reminded us that winter is not really over, even though it really seems like we haven't had a winter.  I think us garden folk are feeling a bit guilty about this, but I remind gardening friends of the horrible winter of 2009-2010, and we tend to agree that we are due this mild winter.

I worked on grafting some maples today.  I have to digress and let you know that until last year, I was convinced that I had no ability to graft anything.  I attempted to graft apples in a Plant Propagation class at the University of Minnesota, and I think all four of them promptly died, even though I tried to cut the scion and rootstock with surgical precision.  We had a grafting inservice training for staff in 2010, and I tried to graft some gingkos and lacebark pine.  The ginkgos took, the pines did not.  I quickly found out that everyone's gingkos were successful.  Apparently, they are very forgiving.  I tried to graft some limber pine from a small disjunct population near Mount Rushmore in South Dakota, but those failed too.  Then I finally met success with Algerian fir.

This is Algerian fir, Abies numidica.  Firs don't generally do well in Washington, DC, but this one has been vigorous and healthy for the twenty years I have known it.  I think it was planted shortly after I started at the U.S. National Arboretum, and I have enjoyed watching it grow.  At any rate, I grafted about twenty scions from this tree on Abies nordmanniana rootstock, and I was shocked when the buds on the scions began to grow, signalling success.  Here are the resulting plants:

How did I achieve success?  I think it was a change in aftercare methods.  Our prior attempts put the grafted plants in a humidity tent in the greenhouse to recover and heal.  I think the clear plastic of the tent just kept the temperatures too warm, and heat is not conducive to post-graft healing.  We changed to a method of piling some damp sphagnum around the young grafts, and this seemed to work much better for the firs, at least.  I've been grafting some pines and spruces with this methodology:

The tiny scions are basically buried in the wet spaghnum.  The pots are on their sides to keep the spaghnum in place.  Here's what's under the sphagnum:

Now I'm grafting Japanese maples, and waxing the graft union rather than using the sphagnum.  Hopefully some will be successful.