September 19, 2015


I am really surprised by how quickly the dormant pots of bulbs can come into bloom in the greenhouse. These cyclamen species were complete dormant (above ground) a week ago, when they received their first 'autumn rain storm' from the hose. The Nerine sarniensis pots were also watered last Sunday, and today - a week later, 6 pots have buds extending 4 inches tall. Even the earlier bulbous oxalis  came into bloom in only 7 days.

Hints of autumn here in New England are everywhere - beyond the pumpkin spice everything at the market, the plants are definitely signaling the seasonal shift. Hummingbirds, which seem to be more numerous than ever this week, continue to feed on the salvia and tithonia, but under glass in the greenhouse, the summer-dormant bulbs in the bulb beds which received their first watering for the season, are quickly coming into bloom. Maybe because I've learned to soak them much more deeply than I had been. Knocking a plant  out of its pot, even after a five minute soak from the hose, sometimes shows where the dry spots are. The entire pot must be soaked deeply and completely if one wants a proper root system.

X  Amarcrinum, a cross or hybrid between two distinct genera - that of Amaryllis and Crinum makes a great potted plant for the terrace or sunroom. Outdoors in the summer, and indoors or in a cool greenhouse for the winter, it can grow large and fill a tub within a couple of years. Typically blooming in fall, it is a common garden perennial in warmer gardening zones such as Virginia, southwards.

Every year around this time, I start thinking about whether I should heat the greenhouse house through the coming winter or not. Of course, it doesn't stop me from continuing to buy plants, or plan on what plants to move into the greenhouse first (once it is cleaned and sterilized for the coming season). What will end up happening is that even though I will fret about heating costs, electric bills, how I will insulate the glass walls this winter and how will I ever haul the increasingly heavy tubs of plants back into the space, somehow it all comes together in the end.

Amarcrinum 'Fred Howard' is also quite fragrant. I purchased mine from Plant Delights this past spring. I remember seeing photos of large tubs of Amarcrinum on display at Longwood which inspired me to try a few in pots.

Autumn for me is when an entirely new gardening season begins. I know I've waxed on forever about how I prefer greenhouse gardening to outdoor gardening (the control over the environment, the limits that a smaller, confined space places on you, the magic of snowy days and jasmine, forcing bulbs and warm, moist air and sunshine in January), but truth be told, I think it's really more about discover. In the winter, I can experiment a bit more, like a chef in his or her kitchen or a scientist in a laboratory, and artist in his studio.

Early September is the time to start seeds of winter blooming annuals for the cold greenhouse. Many of the Californian annuals or cool weather annuals such as Salpiglossis and Godetia which may not do well in our summer heat and humidity make terrific potted plants in the winter under glass. This is something I have learned from nineteenth Century gardening books which often provide planting schedules for estate glasshouses and their crops. 

It's been a week since I sowed my first trays, and some seeds are already growing. Here, pots of Layia platyglossa or Tidy Tips, a yellow and white western US wildflower are already germinating.

The greenhouse allows me to set up projects which are somewhat controlled, build collections which can be displayed and appreciated at eye level, closely and in details one can obsess about, and it provides me an platform on which I can step back and appreciate more - time to observe. A gallery, a studio, maybe even a church.

The Firecracker Vine (Ipomoea lobata) racemes are beginning to open. As easy as morning glories, it's a vine we rarely see in gardens. Like many annual vines, it blooms late for us, often just before frost which will arrive in a few weeks, the brilliant red and yellow blossoms will nearly cover the long vines as they open and extend upwards.

Maybe this is why the Victorians created ferneries - because plain, ol ferns are nothing but forest weeds when set out in the vast, generic shady nooks of an outdoor garden, but when carefully collected, labeled and displayed in a staged fernery - they transform into magical theater - museum-like because they are on display, yet more approachable since one can touch them and study them, comparing the various species and their differences.

This completely yellow and white selection of the Firecracker Vine  named 'Citronella' is a more difficult variety to find in the US ( it's available at Chiltern Seeds), and it's new for me. I love it when there are color breaks like this.

I suppose, it's all about experience then, some of us can just enjoy plants better when a frame is set around them. Pottery, the physical design of both container (pedestal) and the "wall" of the gallery (the greenhouse glass, or lattice. The entire, collective visual experience of 'presentation'. I like that sort of thing.

This tall Four O'Clock, or Mirabilis jalapa is a pure white 'wild' form I received as a gift from Blythewold Mansion. I adore it - fragrant, and as tall as I am, the only creature who loves it more are the hummingbirds.

There is another thing about keeping a greenhouse collection that I've touched on in the past, and that is the inevitable boredom of maintaining a collection one keeps year to year. Sure - plants are living things, and they grow ( and grow, and grow), and one cares for them, and cares for them, and to be honest - some just grow less interesting. Horticulture is not just about keeping things, it's about learning and discovery. One of my greatest fears is reaching that point when I have grown everything, and then nothing means anything anymore. Over-familiarized I guess. To avoid this, I try to raise some new things each year. I hope that I don't run out of new plants to try!

This year, I am planing both repeat rituals and discovery projects. Freesia are something I have not grown for a while, and Dutch Iris (those from bulbs) have never made it into my greenhouse beds. I still am seeking carnations (sources please?) to set out in a cutting bed, but I just may plant ranunculus, since last year, my anemone crop was a bit disappointing.

Do you remember all of those Lithops seeds from South Africa that I sowed last August in an attempt to start a collection? Well, some are growing nicely, even though an early watering accident killed about 2/3rd of the hundreds of pots that I started. I now have about 30 pots of different species and selections started, most only have a few seedlings per pot. 

One thing I am trying which is new, but which has been on my bucket list for many years now, is trying winter annuals - species which were once so popular in the 18th and 19th century in cold greenhouses, but which today are never grown ( probably because few people bother with keeping a greenhouse). These annuals, at least here in the Northeast, are often those which might be common in California or in cooler winter gardening areas where some tender plants can be grown, but which could never be grown in the summer, since our summers are too hot and humid.

My seed orders arrived this week for salpiglosis, nemesia, swan island daisies and other cool-loving annuals which reportedly were once s standard potted plants for winter greenhouse displays a hundred and fifty years ago. Sown in late August or September, they promise to make flowering plants for mid to late winter and early spring. We'll see.

This little bulb is indeed a rarity - a relative of the common houseplant known as the 'Spider Plant'  (C. comosum). This bulbous gem is Chlorophytum chinense - and it's one of 175 species in the genus. I know - sometimes rarities are rather boring. Now, if I could only grow C. borivilianum (Google it).

So, yes - it looks like I will at least start to heat the greenhouse this year! The reasons are many, including ALL of those chrysanthemums which will need to come in for display in November. I may begin moving plants in later this week, of course, while Joe is away conveniently at the national terrier shows in Montgomery County, PA for a week. Funny how he times it perfectly every year!

I don't tend to save much garden seed aside from alpines and species, but this Asarina purpusii 'Victoria Falls' vine has lovely seedpods, and even though it is a named cross, I think I may save some seed to see what I could grow from it next year. The mother plant will be cut back and brought back into the greenhouse for some winter bloom. 


  1. I also have been growing annuals in my cold Virginia greenhouse for several years, mostly calendulas, stock etc. but like you have gotten bored so I may try Godetia and Salpiglossis. This year I am going to try to grow the Garvinea Gerberas for cut flowers. Supposedly, they need temps under 50 at night to set buds. By the way, I have loads of Browallia americana in my outdoor garden and in bloom. They re-seed like mad and I have not bought seed in over a decade. Gary

    1. HI Gary - I haven't thought about growing calendulas nor gerbera - I wonder where I might find some? I too have Browallia americana in the outdoor garden, they are covered in bloom right now - I have never grown them before - maybe they will self seed a bit? Not sure about the cold hardiness, but I have plenty of self-sowers that do survive such as Nicotiana langsdorfii, especially near rocks where it is slightly warmer.

    2. Hi Matt: Browallia americana is not hardy but the self-sown ones came up this year despite -5 degrees here last winter. I am growing the Garvinea gerbera supposedly hardy to zone 7 outdoors. I saw them at a nursery in South Africa and searched for them in the U.S but had no luck until I happened to stumble on them being sold on the QVC network! You can also find them at Roberta's garden online. One of them was a runner-up for best in show at the Chelsea garden show last year. Gary

    3. Now you have me on the hunt for this Garvinea gerber a - so interesting, how sis I ever miss this on QVC? Ha - although, I have to admit that I've stopped a few time to watch segments. Maybe now I will actually buy something. My annuals that are more tender sometimes survive our winters in micro-climates between the bluestone pavers. Few survive in the open garden.

  2. Anonymous6:40 PM

    dear matt
    i love the way you wrote this post, you have brought a reverential quality to it that is valuable, because everything we do that we love should reflect that. hoping that your greenhouse is able to continue as the locus of your church....
    all best,
    ~ 02568

    1. Oh my, thanks! :) Sometimes I do get a bit sappy!

  3. Anonymous4:54 PM

    hi matt! i'm hoping to force some lily of the valley pips this winter, an idea i had picked up from one of your previous posts (thanks for that, by the way!). sowing cool annuals also sound like a lovely idea. happy autumn!
    ps--those baby lithops are too cute!

    1. Do try some lily of the valley, I never regret it, but be patient - they force easier the later you wait. A late february Forcing is easier and faster than early January. I have no idea how old timers ever forced plants for Christmas!


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