Sunday, July 13, 2014

Diverse Growing Conditions

Over the last several years I have delved into rock gardens of various sorts, gravel gardens, trough garden, meadow gardens and my latest, a "well-drained" garden. They have all been and continue to be great learning opportunities. I am introduced to new challenges of all sorts and get to grow plants that I had previously killed, just admired from afar, or had never even heard of. Below is a sample.

Well-Drained Garden:
I have killed Euphorbia x martini 'Ascot Rainbow' (above) three times. Each planting site had better drainage than the last on the theory that the plant, which the label claims to be hardy in zone 5, died from being too wet in the winter. The third effort was in the very sandy soil of my well-drained garden. Rather than take the next step and put a roof over the plant for the winter I am concluding that the claims on the label are exaggerated and it is NOT hardy in zone 5.
On the other hand my well drained garden prompted me to experiment with previously unfamiliar Silene laciniata, Dianthus amurensis, Muhlenbergia reverchonii, and Stachys lavandula all with gratifying success. Pictured above is the rather insubstantial but engaging Silene laciniata.



Gravel Garden:
I didn't set out to have a gravel garden. I built a rock garden/retaining wall along the edge of my gravel driveway and was thrilled and fascinated to see what decided to migrate into the driveway. In the above picture you can see that forget-me-nots (Myosotis sylvatica) descended from the wall to colonize the gravel. Others that have done the same include Verbena 'Annie", Corydalis cheilanthifolia, Festuca glauca, a dwarf form of Lychnis flos-cuculi, Aetheonema schistosum, and Phemeranthus calycinum. Now I am starting to experiment with conscious introductions to complement the many desirable volunteers.
Above is the Phemeranthus calycinus (aka Talinum calycinum) as it makes an interesting wash over the garden with its easily edited and unobtrusive seedlings.


Monday, June 23, 2014

Fragrance

Abelia mosanensis (Fragrant Abelia) is an underused must-have for fragrance.

Close-up of Abelia mosanensis
 
Nothing compares with the a well fragranced rose such as Rosa 'Gertrude Jekyll'

Fragrance in plants is a multi-faceted story. I never fail to stop to smell the 'Gertrude Jekyll' roses when I walk by their flowers while at work. And I still mourn failing to move some peonies with me that were so fragrant their cut flowers could perfume a large room. In retrospect I never appreciated how rare that intense fragrance is in peonies. On the other hand I am repeatedly irritated by claims of lovely fragrance that in-truth require deep inhalation with nose squarely imbedded into the flower. And, of course, there is the long established kvetch about breeders neglecting the fragrance trait in otherwise fragrant plants like roses (and peonies, I suppose).

The sense of smell powerfully influences our memories and can bring back long forgotten experiences. The smell of petunias, which is more distinctive than fragrant, immediately brings me back to my early childhood.

Fragrance can transform an evening. For example the smell of the flowers of Brugmansia (Angel's Trumpet) brings back an early evening walk in Balboa Park in San Diego. As I was walking along I was suddenly aware of a most wonderful fragrance which I was able to trace back to a Brugmansia tree. The flowers that emit their strongest fragrance in the evening bring a special delight to what is probably the most emotion laden time for visiting a garden. Nicotiana sylvstris, flowering tobacco, is another memorable plant that contributes to the pleasures of an early evening in the garden, and night-blooming cereus is worthy of a special evening pilgrimage to an enlightened greenhouse.

Another sort of fragrance experience is provided by the likes of Abelia mosanensis (Fragrant Abelia) and Viburnum carlesii (Koreanspice Viburnum). These two shrub's fragrance can transform an entire backyard. Curiously around my part of the country the Abelia most often seen is Abelia x grandiflora, a half hardy shrub with forgettable fragrance. (I really can't recall.) On the other hand Abelia mosanensis is fully hardy and made our deck a sensory delight for about two weeks this spring.

Thursday, May 29, 2014

Boon and Bane

Symphytum azureum is not your grandmother's comfrey. Here it is in bloom on May 9th.

The mass of blue at the top of  the picture is Symphytum azureum on May 4th demonstrating its ability to function as a groundcover and suggesting its potential to spread.
 
This October 24th picture demonstrates the ability of Symphytum azureum to grow through thick mulch and for its leaves to persist well into the fall.



Symphytum azureum (The common name (comfrey) is very misleading. This is NOT the comfrey that most people know.) It is one of those plants that is both exceptionally useful and a nuisance to get rid of. I am just coming off about a ten year honeymoon with the plant where everything it did pleased me, so I am surprised at how little is seems to be known and offered. Curiously, a Google search brings up mostly sites outside of the U.S. An issue over its proper name may be one reason.

It spreads slowly. It isn't what you would call invasive. Inexorable would be a better description for its slow but relentless spread throughout a suitable growing site. So now after a decade it has reached the boundaries of where I want it to be, but I find it does not come with an off switch.  It would not be very compatible with mixed perennial plantings. I fear it would insinuate itself into most anything herbaceous, although I imagine larger plants could readily grow through it. By the way the web site for the German nursery Lorenz von Ehren says that prompt deadheading will slow its spread.

What has been exciting to me is that it is both attractive and very successful at developing a dense stand under the heavy shade of a sugar maple and a massive Norway spruce. For the very patient or the free spender it makes a great groundcover for the shade. The catch is that it must be contained (or perhaps diligently deadheaded).

On the whole it is a very useful plant that would bring considerable joy to gardeners, especially where an attractive solid stand of a highly shade tolerant groundcover is wanted.

Wednesday, May 7, 2014

The Wow Factor

 
 
 
Gentiana verna

Sometimes plants just knock your socks off when you first have success growing them. Jeffersonia dubia certainly had that affect on me as did Gentiana scabra. Now another Gentian has bowled me over, Gentiana verna. I am growing it in a trough garden with excellent drainage, and it is blooming after its first winter. I read that it is short lived, and I see no mention of self seeding so I guess I had better enjoy it while I can. What an amazing blue!

Monday, February 17, 2014

Inverted Growing Season

Cyclamen hederifolia flowers emerging through Carex platyphylla foliage in September

Cyclamen hederifolia in full leaf in mid January, finding plenty of growing room, growing with the dormant Carex platyphylla seen in the previous image

Arum italicum fruiting in August with conspicuously dormant leaves.
 
Dentaria (Cardamine) diphylla still looking fresh in March after being around all winter and before going dormant in the summer
 
Sternbergia lutea blooming in the fall as its leaves emerge from dormancy

I grow at least four perennials that emerge in the late summer or fall, remain green all winter and then go dormant as summer approaches (Dentaria (Cardamine) diphylla, Arum italicum, Sternbergia lutea, and Cyclamen hederifolium). Weird. I suppose that makes sense in a Mediterranian climate where the winters are mild and moist and the summers are hot and dry, and that is exactly where three of these four are native.  But somehow they survive in climates with cold winters and relatively moist hot summers.  Dentaria diphylla, on the other hand, is native to the eastern U.S. So where did it acquire this inverted growing season behavior? I bring this up not for botanical reasons but rather horticultural. How do you take advantage of this habit to enhance your garden? I mean, what a gift to have plants that grow when others aren't. They need to be paired up with compatible companions, but there's the rub.

I pride myself in my efforts to orchestrate the sequence of emergence and decline of perennials in my garden and have several combinations that I shamelessly tout as exemplary. But, alas, this growth habit I am calling "inverted" is challenging. I think I found a nice combination for the Cyclamen. I combined it with Carex platyphylla (Silver Sedge). The sedge is low growing enough that when the otherwise dormant Cyclamen sends up its flowers in mid summer they poke through the sedge and make a nice display. As the Cyclamen leaves are emerging late in the growing season the sedge leaves make room for them as they go dormant. It is all very tidy, but I haven't been able to do anything comparable with Arum italicum or especially Dentaria diphylla. (For hardiness reasons I grow Sternbergia in a pot.)  Arum italicum produces stalks with bright red fruit in August when the leaves are gone. It makes an interesting affect on bare ground, so there is a reward for not finding a sort of mirror image growing companion, but I would be more satisfied if I could. I have been growing Dentaria diphylla for six or seven years and only recently realized why it was so unsatisfactory in the summer. I just have to apply myself to this challenge. That (and so much more) is what I love about gardening.

Friday, December 20, 2013

Old Dwarf Conifers

Those cute little balls of evergreen dwarf conifers seem like they will be small forever, but eventually, of course, they get big. It is sad, sometimes to see old dwarf conifers that have never been pruned because many varieties are so dense they form a solid but shallow encasement of foliage that reveals none of the plant's branching architecture. I did a program recently on dwarf conifers and dug up many of my old slides which included pictures of old plants that, because of their dwarf and slow growing nature, had acquired an interested sort of aged look to them. I am eagerly pruning my own dwarf conifers to try to accelerate that look.

An Austrian pine (Pinus nigra 'Nana') seen many years ago growing at the National Arboretum in Washington D.C. had acquired a venerable and distinguished look while remaining within a reasonable scale for most landscapes.



Japanese umbrella pine (Pinus densiflora 'Umbraculifera') is not a dwarf, but it is a fairly small, slow growing tree a with distinctive growth habit. If it isn't pruned it grows into a very uninteresting solid mass of foliage. The plant pictured above, as seen many years ago at the Cincinnati Zoo had been beautifully pruned to show off its many attractive features such as the orange bark, vase shaped growth habit and flat topped branching.

This dwarf eastern white pine (Pinus strobus 'Nana') also seen a number of years ago at the National Arboretum in Washington D.C. has a fascinating form that in a better setting and without the gravel and ring of exposed edging could be the centerpiece of a wonderful garden composition.
 
My own dwarf eastern white pine is only eight years from the container nursery and already I think it is starting to show some interesting branching habits that will only become more interesting with age if I prune with care. It may be hard to imagine, but shortly before taking this photograph I opened up the interior of this plant and removed a great number of branches.

Thursday, November 21, 2013

Growing Weird Plants



I like to grow weird plants like Ephedra, and they can be considered weird for any number of reasons. Anyone who studied plant taxonomy would have to consider Ephedra weird because it just doesn't fit into the preconceived notion of a cone bearing gymnosperm. It seems like a remnant of evolution. They are also unusual for their essentially leafless habit, although in their typically arid habitats, that trait is shared by many. Finally the alkaloids contained within the plant have a long history of use and abuse which gives the plant special interest. Gardeners are often collectors, and there is great pleasure in being able to say, "Oh yea, I have that."

When I was thinking about whether to include this plant in my blog I checked the Internet for images of Ephedra minima, which is the one I have been growing since 2008. Most pictures show the red fleshy cones, which I also illustrate, but I didn't see any with the interesting growth up a vertical crevice with the leaf-like switches lined up in a similar vertical orientation as if the plant is flowing up the rockery. My weird plant also makes a nice aesthetic contribution to my rock garden.

Thursday, October 17, 2013

My Flat, Rock Garden

I love my tiny garden compositions. Judging by the current enthusiasm for fairy gardens and ongoing enjoyment of gardens for model trains and terrariums diminutive garden compositions seem to be popular. I guess I get my diminutive garden outlet through my rock gardens and in particular, for the sake of this edition of my blog, through my flat, rock gardens. One in particular has proven particularly satisfying, so I am in the midst of expanding and improving it. The photographs below portray a sampling of some of my favorite inhabitants.

I have access to a quarry's scrap sandstone rocks that typically have at least one flat side and are about four to eight inches thick. They are otherwise irregular.  I lay these down like a patio leaving abundant planting gaps where the irregularly shaped rocks don't fit together. I backfill with sandy loam soil.

Above is one of my favorites in this garden, Veronica prostrata 'Wine'. Although the growing conditions are very different from alpine screes, to me this sort of scene reminds me of that rocky, sparsely vegetated landscape.
 
This tiny clump of Lewisia 'George Henley' (above) is my only surviving Lewisia and it has been growing as this little clump for about seven years. Those sandy cracks between the rocks must be well drained, because I think my Lewisia growing in other sites died from winter wet. Its biggest threat is from encroachment by the neighboring Dianthus. See below.
 


A dilemma that always seems to loom for me in my rock gardening is what to do with expansive plants such as the above Dianthus gratianopolitanus 'Feuerhexe'. I relish its success in the site but don't want to lose the precious little specimens it engulfs. A balance must be struck and I have been brutally whacking the Dianthus back lately. Notice the above mentioned Veronica prostrata in the lower right hand corner for a size perspective.

I thought I had lost my fall blooming, questionably hardy Leucojum autumnale (above) from this garden, but I was thrilled this fall to find it growing and in bloom.
 

I had also been missing the flowers of my fall blooming crocus (Crocus kotschyanus)(above) from this garden but it appeared in good blooming order this year. I saw the spring leaves but have had problems in other gardens losing track of these little plants in mid summer after the leaves disappear. I think in this case the flowers were obscured by floppy bordering plants such as the Japanese anemone seen here. I have since beaten them back.

 
And finally, I want to mention this long time survivor of this garden pictured here several years ago before the stones became weathered and moss covered. This year's photographs of the plant don't do it justice. Its Antennaria dioica 'Rubra', a red flowered selection of a common native inhabitant of thin infertile soils around here. My rockery seems to suit it just fine and its another example of how I don't get too hung up on beating my head against a wall trying to grow true alpines in my hot humid climate.