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Self-Sowers Can Help Fill In Your Garden

Posted: April 17, 2012

Calendula

Calendula

Self sowers can come in the form of annuals or perennials, but today, I would like to talk about annuals. I define self-sowers as annuals that keep coming back each year. Most can be easily started from a pack of seeds sown directly into the garden soil, so now is a good time to think about what you would like to start, and have the seed on hand and ready to sow when the time is right.

Some self-sowers are much better behaved than others. For instance, in my garden, calendula (pot marigold), have come back strong for years right in the same spot I had them the year before, while my tall verbena (verbena Bonariensis) come up everywhere. They are especially fond of the minute cracks between the bricks of my sidewalk! Why would I keep them? They are beautiful, and add an element of personality to my garden that I can't find with anything else. Even more important to me, they are a wonderful butterfly magnet. In fact, Ron Richael, in his book called, Attracting Butterflies, rates it as the number one butterfly attractor even above Butterfly Bush (Buddleia). Just to be sure, I keep some right beside my butterfly bush, and, I have to say, most days I can't count all the butterflies that are fluttering around the two.

Self sowers can save you money because you don't have to invest in them each year as you do with other annuals. In the behavior department, most of them fall somewhere between the calendula and the verbena bonariensis. The fact that they spread their seed around often results in some wonderful garden designs and combinations you may not have thought of yourself. They also add to the continuity of your garden design by repeating themselves across your garden bed.

Beginners often make the common mistake of scattering unfamiliar seed across their garden without marking it. Sometimes they actually buy a seed pack labeled " Wildflowers". Before they know it, they have a hodge-podge of seedlings with no idea of what they are. They don't know which are desirable plants and which are weeds. Generally, they will then do one of two things: One, they will do nothing, letting them all grow into an unbelievably, unmanageable mess, or, two, they will hoe them all out and plant marigolds!

When you introduce a known self- sower to your garden, start by using some sort of marker to identify the spot where you started it. Write the name of the plant in your garden notebook or journal. Include a picture, either from the seed pack, the marker that came with the plant, from a catalog, or one you took yourself. Next year those seedlings will come back in pretty much the same spot. Take a picture of the seedlings, and add it to your reference. Then if you find a couple more somewhere else in your garden, you will be able to recognize them and decide if you want them there or not. Once you know you can recognize the seedlings from that plant, go ahead and introduce something new.

IF YOU WANT TO GROW SELF-SOWERS, YOU MUST LEARN TO IDENTIFY THE SEEDLINGS! Books can be helpful, but nothing beats knowledge gained from first hand experience in your own garden.

In addition to being able to recognize the seedlings, there are a few other MUSTS for growing self-sowers:
1. You must have good soil. Seeds won't germinate in hard clay. Organic matter in the form of compost or mushroom soil is needed.
2. Wait until your self- sowers are established in the spring before you mulch.
3. Do not cultivate the areas where you are expecting self-sowing to occur.
4. Never spread Preen where you want seeds to germinate.

Once the seedlings appear in early spring, you will want to weed out the smaller, less vigorous plants. In some cases, you must be prepared to pull out many seedlings, either because there are too many, or because they are in an undesirable spot. This is obviously the biggest disadvantage to encouraging self-sowers in your garden, but, in my opinion, it's well worth it for all the added beauty you receive. The good news is that young seedlings are extremely easy to eradicate. Sometimes I just take my hand and rub it over the soil.

Many times you'll want to save your seedlings to transplant to another spot, or give them to friends. If transplanting, dig out the little plant and handle it by its roots, never its stem. I like to prepare a small tray of potting soil and carry it with me. An egg carton works well. Then, as I dig out the baby, using my garden knife or trowel, I immediately place it in the potting soil for transport. When transplanting, always water in well, gently wetting the soil not the plant.

I have noticed that among my gardening friends, plants sometimes tend to produce differently in different people's gardens. This may be a result of differing soil amendments, different watering practices, different soil pH, etc. The result is that one gardener may have success with one plant, while another gardener will have success with something different.

Some annuals that have been reliable self-sowers for me in my garden over the years include: Amaranthus (Loves-Lies-Bleeding), Sweet Allysum, Calendula (Pot Marigold), Cleome (Spider Flower), Columbine, Cosmos, Dill, Forget-Me-Nots, Hyacinth Beans, Lychnis Coronaria (Rose Campion) a biennial, Portulaca (Moss Rose), Poppy, Sunflower, moss Verbena, and tall Verbena.

One of my favorite plants is the Johnnie Jump Up (Viola tricolor). I bought a seed packet of them many years ago and, true to their name, they jump up everywhere. They will be blooming in March along with the daffodils, and continue into summer. People just exclaim over them, and are always asking me for some. After a while they will start to get a little leggy, or get in the way of other garden plants, and I just yank them out. They are extremely easy to manage, and no matter when you rip them out, they'll be back!

Growing these self-sowing flowers is always a gamble. You never know for sure what you are going to get. But isn't that part of the fun and challenge of gardening?

Just be aware that there is a difference between vigorously reseeding, and invasive. When a plant is placed on the PA "invasive" list, it means it is crowding out native plants that are important to the support of wildlife in the local area. Invasive plants should never be included in your garden. An example of a common invasive flower in our area is purple loosestrife (Lythrum salicaria). Although it is beautiful, purple loosestrife is a very dangerous plant, especially near waterways. By crowding out plants that our wildlife would use for food and shelter, it destroys their native habitats. You may think that having a little in your private garden won't hurt anything and that you can keep it under control, but you can't control the birds and the wind which are two ways plant seeds are spread.

If you have a question concerning a specific plant, give the Penn State Extension Service a call.

The Penn State Master Gardener Hotline to answer gardening questions is open April through September, on Mondays and Fridays, from 10 am to 2 pm. Call 717-334-6271 or bring in your samples for a diagnosis to 670 Old Harrisburg Rd, Gettysburg.

Barbara Mrgich is a Penn State Extension Master Gardeners from Adams County.  Penn State Cooperative Extension of Adams County is located at 670 Old Harrisburg Road, Suite 204, Gettysburg.  Call 334-6271.