A Glimpse into the Garden: March 2014

A monthly gardening update by OSV staff horticulturist Roberta McQuaid

This behind-the-scenes glimpse of the Village gardens will explore a range of topics including what’s growing in our gardens and the culture and history of specific heirloom plants. We hope that you will find this monthly online feature informative and perhaps it will enrich your next visit to the museum - maybe even adding to your own gardening adventures at home.

The OSV greenhouse heats up in March

I just love March in the Old Sturbridge Village greenhouse!  It is the month when the space really starts to illustrate that we have turned the corner from winter to spring.  The signs of this transition are everywhere!  Scented geraniums are full of dainty pastel blossoms.  Succulent new growth is seen on the bay trees and rosemaries.  Overwintered canna rhizomes are given fresh soil and a new pot to get a jump start on the season.  But perhaps the best sign that spring has arrived are flats and more flats of seeds and seedlings on the propagation bench. 

We grow transplants for three distinct purposes at the Village:  Museum Program, Maintenance and Retail Sales.  Costumed interpreters plant our seedlings in the herb garden, the household gardens around the Center Village and at the Bixby and Freeman Farm gardens. They are heirloom and true to the character and timeframe the individual garden represents.

We also grow a number of plants for use by the gardens that Maintenance Department is responsible for, namely those at the Lodges, the museum entrance and those adjacent to the Visitor Center and Museum Gift Shop.  Modern varieties can be used in these spaces.  Sometimes I find it funny to walk through the greenhouse and see a new “Proven Winner” growing next to a plant well known in the early 19th century!  Lastly, we grow a hundreds of heirloom tomatoes, annual and perennial flowers and herbs for use at our plant sale and tomato giveaway that is held every year in mid- May.  This year the date has been set for May 17th.   

An insider’s guide to starting your favorite perennials from seed

Most gardeners have tried their hand at seed-starting at least once in their lives.  My first experience involved an egg carton, some potting soil, a few marigold seeds, and a window sill, of course.  I must have been about ten years old.  I can still recall how amazed I was that a live plant grew from what appeared to be a dried up sliver of straw.  It was even more enthralling to see flowers form a couple of months later after my offspring made its way out to the garden. 

While early March is still  a couple of weeks too early to start marigolds or even tomatoes indoors, it is the perfect time to sow the seeds of many of your favorite perennial flowers.  Sure, it involves a bit more than an egg carton and a window sill, but out of it all you’ll be rewarded for your hard work with blooms that return to the garden year after year.  Here are a few pointers that I have gleaned from the last 19 seasons of starting perennials from seed.

The general idea is to provide a moist, warm environment for the seed to germinate and then a semi-warm, well-lit environment for the plant to grow on.  Therefore, props are necessary components if you want to be successful. Invest in some heat mats and set them at 70 degrees to provide bottom-heat.  As far as light goes, the window sill won’t cut it unless you are extremely diligent about turning the plants many times over the course of the day- even then, “stretch” is likely to occur.  Instead, adjust a “shop light” so that it can be raised and lowered easily.  One cool fluorescent bulb and one warm are recommended but two cool work fine in my experience.  Forgo garden soil or even regular potting soil in place of a finely milled seed-starting mix.  Sterilize shallow containers of choice in a 10 percent bleach solution before using them.

Sow teenie seeds on the surface of moist starting mix; small seed can be sown in shallow furrows.  Space as best you can by folding an index card, placing the seed in the fold and tapping the card with your finger. Larger seeds can be buried a quarter of an inch apart.  Cover with a humidity dome or a clear plastic bag propped up like a tent and place on bottom heat. Mist the soil of surface-sown seeds occasionally.  When thoroughly dry, soak the container in a few inches of water; it will absorb moisture like a sponge.  Once germination occurs, remove the dome or bag and place the seedlings within a couple of inches of the shop light off of the heat mats.  Adjust lights accordingly as growth occurs.  Liquid fertilize at one-quarter to half-strength after a couple weeks and transplant into small, individual containers or cells after true leaves form.  Easy does it!

I love to grow heirloom plants from seed- after all, unless you buy them at our plant sale or a specialty nursery they are hard to come by commercially.  Here are the specific seed-starting requirements for seven of our favorite antique perennial flowers.

Bellflowers (Campanula persicifolia) bloom around the Fourth of July- fitting, I guess, for flowers that are either blue or white!  Seeds of this genus germinate best if they are no more than a year or two old.  Since seeds are tiny, therefore sow on the surface of the soil- firm gently but don’t cover at all.  Bellflowers take about a week to sprout. 

Blackberry Lily (Belamcanda chinensis) has orange flowers reminiscent of freesia (less the scent!) and sword-like leaves similar to those of iris.  Neither of these two distinguishing characteristics give the plant its name, however.  That job is left for the seed clusters that appear late in the season.  They do indeed look very much like large blackberries.   Shiny black seeds should be buried in twice their thickness of soil and about one-quarter of an inch from one another.  Don’t be alarmed if a fair amount of time has gone by and nothing seems to be happening: blackberry lily can take upwards of a month to germinate.

The orange flowers of Butterfly Weed (Asclepias tuberosa) are loved by gardeners and winged creatures alike come midsummer.  Sow the seeds of this native perennial in shallow furrows; germination should occur a week to ten days later.  Be careful not to over water these seedlings.

Columbine (Aquilegia species) seeds need a cold, moist period to break dormancy.  Mix seed with an equal amount of moistened potting soil and place in a sandwich bag in the refrigerator for a month.  Remove and sow the mixture on the surface of the soil.  Do not cover seeds with additional soil- even though these seeds aren’t as tiny as others, light is necessary for germination. Sprouting should occur in 2-3 weeks.  Plant columbine alongside late blooming bulbs for a wonderful springtime combination.

The large yellow flowers of Evening Primrose (Oenothera missouriensis) fade with the noon-day sun, only to be replaced by more blossoms in late afternoon.  Sow seeds thickly in shallow furrows and expect only half to come up.  Germination will be sporadic over the course of a month’s time.

Sow Hollyhock (Alcea rosea) seeds in individual cells to prevent fast-growing roots from tangling.  Mice love this seed especially, so take care of any critter troubles beforehand.  Germination will occur sporadically, beginning 7-10 days from sowing.  It’s amazing to think that in just over a year’s time, a six foot spike of flowers will result.  Amazing ability from a seed no bigger than the tip of your pinky finger!

Pinks (Dianthus species) are valued for their old-world charm and heady fragrance.  Seeds can be sown in shallow furrows barely covered with soil.  Keep this one off of the heat mats to prevent lanky, weak seedlings; sixty degree temperatures at germination are preferred.  Sprouting should take place in 10 days or less.

Go ahead and give these perennials a try.  Sure, they may require a bit more work than the egg box marigold I mentioned, but they will no doubt be worth the effort.  Just imagine the pride you’ll feel when you gaze out at the backyard border, knowing that you grew them yourself!