Thursday, May 25, 2017

The Weird Dogwood

Yes there is a strange dogwood in our yard.  I would have had it cut down as it has dieback on one major limb and is past its prime, but having seen it flower I knew it was something special so it was spared from the saw.  In fact I had some nearby hemlock branches cut so it could get more sun, and I do water it when it gets too dry, as was often the case last summer.

 The flowers don't quite open, and most closely resemble a subspecies of Cornus florida that occurs in Mexico, ssp urbiniana.  Yet I find it hard to believe the previous owners would have gotten their hands on this much sought after subspecies.  They did like pretty bushes and planted a lot of azaleas and rhododendrons, most of which remain, along with forsythia, lilacs, andromeda, and other common shrubs, some of which I have eliminated or reduced. But if this dogwood is not urbiniana it must be a mutant which coincidentally results in the same caged flower appearance as ssp urbiniana.  It is attractive in a different sort of way, and I am trying to propagate it.  Cuttings that I took and also brought to NYBG failed, so I am trying to ground layer it.  I also have pots of seedlings coming along but as dogwoods are self sterile from what I read, I assume the seedlings have a regular dogwood father.  What I don't know is if the caged flower trait is dominant or not, so I won't know what the offspring will look like until they bloom, which could be a long time.

The tree has been making more flowers since I had the hemlock branches in front of it removed.   I still need to remove a dead limb from the tree, but overall I think it is liking the renewed attention it is getting since we got here.

 Many flowers eventually open but never flatten out like normal dogwoods, and the bracts have that odd keel or fold in their middle.

Odd indeed but I like it.

Its Dianthus time again

A minute cushion forming species which I got from rock gardening friends who got it from Wrightman Alpines.  It was given to me as a small rooted cutting and has turned into a perfect "bun" in a couple of years.

This one is an interesting shade of pink which I rather like

Its that time of year when each day brings new surprises.  Despite the often less than favorable rainy/cloudy weather this spring, the dianthus in my gardens have done well.  No doubt the mild winter helped, and also the generally cool spring temperatures tend to favor them.  Most of what I have, and there are many dianthus here, are grown from seed from the exchanges (NARGS, SRGC) and my own seeds from the ones I grew in the school garden some years ago.  A few linger on at school but the voles seriously culled their ranks during one of our snowier winters a few years ago. I also haven't been as diligent at weeding the school gardens as I was before we moved to this place where my gardens take up much more of my time than they did in our prior residence.  When one gardens on over half an acre (minus the footprint of the house and driveway, but counting in some of of the patios as there are quite a few things that really do well in the cracks between bricks or slate) it takes a lot of time and effort.
Many of the dianthus pictured here and others came from left over NARGS seeds which are redistributed to the local chapters after the two main rounds are done.  So few people these days seem to be willing to try and grow from seeds, and indeed many seeds can be challenging or take time to produce mature plants, but dianthus is not one of them.  Dianthus seeds germinate fast, and need no special conditions apart from reasonably mild temperatures, decent soil and moisture.  They grow quickly and often flower their first year, and certainly will do so their second year.  They do have certain demands, for one they must have good sun exposure, and also they need good drainage.  In the areas where I have planted a number of them I have amended the heavy soil we have with coarse sand ("road sand") which they seem to like.  They cross readily and a myriad of different flower colors and patterns emerge, as well as fringed petals on some.  They also smell wonderful, and if you get a particularly nice plant from seed, it can be propagated easily from cuttings.
Few pests bother them apart from herbivorous mammals.  Voles can be especially destructive during winter if there is a long period of snow cover as they munch through the cushions and line their trails with dianthus leaves.  Deer will sometimes bother them but most of mine are in the back where posts and mesh keep the deer out and in the front I use Liquid Fence every few weeks to repel the few deer that are in this area.  Dianthus also don't like a lot of organic matter near them so don't put mulch around them, they prefer gritty soil that is not too high in organic matter.
There are some other species that will flower later, among them D. amurensis with blue-lavender flowers and Dianthus taiwanensis (or a Taiwanese form of superbus) which I grew from seeds I collected in Taiwan.  The latter flowered profusely their first growing season, and all of them survived the winter in great shape, and are in bud right now.  I also have some cultivars from Santa Rosa Gardens which are more carnation like.  They tend not to form seeds and are a bit fussier than the seed grown singles.  In addition I grow the Chabaud carnations, they are easy from seed and flower their first year, and some usually survive winter, especially if it is mild.

Wednesday, July 27, 2016

Erythina zeyheri, the Ploegbreker (Plowbreaker)

Erythrina zeyheri

Erythrina x bidwellii

Erythrina is a genus of mostly trees of tropical climates.   Some of our native species do produce a thickened lignotuber from which they can resprout after fire or frost, but in South Africa there is a species which never produces persistent stems above ground.  This species, E. zeyheri, is known in Afrikaans as ploegbreker, the plow breaker, on account of the massive sizes the lignotuber  can achieve.   I saw this species from a distance during a trip to South Africa in 1993 when I was travelling with the late Charles Craib, an extremely knowledgeable person who produced many detailed descriptions of the habitats for a large number of rare and localized South African plants.  He also wrote some books which are hard to get a hold of now, including one on tuberous pelargonium species which I now wish I had acquired when it was first published. We were driving through the Free State on our way to the midlands of Natal where we were to stay overnight with an expert grower of South African streptocarpus, Martin Kunhardt.  As we drove by the dry fields of grass I spied some bright red flowers popping above the grass.  They reminded me of bright red lupines, but we didnt have time to stop and look closer.  Later on Charles sent me seeds of E. zeyheri, and I grew several plants for the NYBG where I worked at the timee.  Some are still there, years later and from what I hear none have flowered in pots.   When grown in pots they need plenty of water during their growing season and they can be dried off for winter.  The enormous prickly leaves and short stems turn yellow and dehisce as the plant enters dormancy.  New shoots arise from the surface of the lignotuber in spring.   In pots it its also prone to spider mites.  
So when I was growing three more of them in pots at home, I did some research and noted they grow in the highveld which would experience freezing temperatures during winters.  I also found out that they tend to grow in wet areas like ditches or near water.  So I decided to experiment with one plant, placing it near the front wall of our house and covering it with dried grass and plastic for winter.   We had a very cold winter, and despite the plastic the tuber was definitely wet during winter as the plastic did not stop water flowing downslope past the spot where it is planted.  I saw a flower spike appear when the plant emerged but it aborted.  Yet I did get to see the enormous leaves grow even larger and there were no spider mites to contend with.  Inspired, I planted my two remaining plants in an area that has become my South African garden.  While I have South African plants in every garden, this area is exclusively for African plants with rare exceptions (such as a Goodenia that was recently given to me and that has some cold hardiness but is from Australia).   One of the plants flowered soon after planting and produced one large seed in a bean like pod.  All three plants were planted so that the top of the lignotuber is several inches below the ground and a foot or more of bark chips were placed over them for this winter.  I find that they can take lots of cold and wet but I am not sure if they can take deep freezing so I protect them in a way that should protect the lignotubers from deep frost.   This spring all three came up, but only the one in front of the house decided to flower.  It produced numerous spikes of vivid red flowers and, with hand pollination, is currently producing several pods of seeds.  
More experience is needed growing this species outside of South Africa, and perhaps even in its native land.  I wonder what exactly regulates flowering in this species.  How much cold can it take during winter?  I have heard that it did not survive in Raleigh North Carolina which has much milder winters than we do, but I imagine the extremely hot summers there might be too much for it.   As far as I know no one else other than the person who tried it in NC is growing it in the eastern US and on a recent short trip to California it appears to either not be common or cultivated at all on the west coast.  It is worth growing even for its foliage alone, and when the flowers do appear it is a visual treat.  I have read that there are albino forms and hope that seed of these variations might one day become available.
I also grow another Erythrina right next to the wall, E. x bidwellii.  This is a cross of two American species and it can die back to the root during cold.  It needs a very protected spot and some mulch over it for winter in order to survive in NY.  It produces long whip like stems with rather wicked thorns and long spikes of red flowers during the summer rather than right after it comes up as does E. zeyheri.  It is also fairly brittle so the stems do break easily and are a bit unruly, at least for me.  But in spite of these faults it does produce some really pretty flowers and is not particularly difficult to grow.  I understand that it can become a small tree or large shrub in places like Texas and Florida where it does not die back to the roots.