Wednesday, 22 November 2017

Self-seeders - friend or foe?

One of the many small joys of gardening is to discover that a treasured plant has set seed and produced a baby without any of your intervention. Some plants are so successful at self-seeding that they can become a nuisance, but I'm a firm believer that one person's invasive plant is another's good do'er. Let me share my experience with you and you can decide.
 Campanula latifolia (giant bellflower) forms tidy rosettes of narrow leaves and produces tall, thin spires of white, or sometimes blue, bell-shaped flowers. It like full sun or part shade, and slots in neatly between other plants. A very useful and pretty self-seeder. 

Bulbs that self-seed = quite a bit of management required

Hyacinthoides non-scripta (bluebells)
We inherited bluebells in the garden (I believe they are our native bluebell rather than the imported, and to be avoided, Spanish bluebell (Hyacinthoides hispanica)). They produce wonderful carpets of blue in early spring, filling the gaps before the mainstay of perennials get going. However, they do have a tendency to spread and are quite difficult to eradicate from unwanted locations. I have discovered that the small, bright-white bulbs are incredibly difficult to dig up as they seem to bury themselves very deep. My new regime is to remove the seed heads before they dry and set seed, and to cut back the foliage on some of them after flowering to reduce the vigour of the bulbs. The seed head is easily removed by a sharp tug on the stem; no need for time-consuming secateurs. Just don't put the seed heads on your home compost!
Bluebells might be hard work to control, but imagine this border without them.

Allium ursinum (ramsons - wild garlic)
Perhaps foolishly, I added ramsons (Allium ursinum) to the mix of bluebells and sweet woodruff (Galium odoratum) planted around the trio of white-stemmed birch trees (Betula jacquemontii Doorenbos) in our mini woodland area. We saw magical drifts of bluebells and ramsons in woodlands on a holiday to the Channel Island of Sark and, romantically, wanted to recreate the same scene at home. Like bluebells, ramsons seed prolifically, so I make sure to remove the seed heads and dig up unwanted seedlings as soon as I spot them. I find that a widger (a slim, pointed trowel) is perfect for this job - if you pull the seedling it will snap the stem and leave the bulb in the ground. I do have mild panics occasionally that I have spawned a monster, but I calm myself with a reminder that they are native plants, beneficial to insects, edible and beautiful.
White-stemmed birch trees underplanted with bluebells, ransoms, sweet woodruff, Disporum megalanthum (on the left), Podophyllum versipelle Spotty Dotty (on the tight between the birch stems) and a blue and green variegated hosta.

I will leave it for you to decide, but unless you are prepared to spend some time in spring, perhaps fighting a loosing battle, I suggest that you content yourself with visiting other people's gardens or public woodlands to view the undeniably uplifting sight of our native bluebells and ransoms.


Tap-rooted perennials = medium management required (but worth it)

Aquilegia (Granny's bonnet)
A cottage garden favourite, aquilegia's are very promiscuous and produce offspring in wonderful variations of the parent flowers. They come in almost every colour and the flower can be single, double, ruffled or horned. The seedlings are easy to dig up and relocate when very young, but once established they put down a long tap root which it is hard not to damage.

Unfortunately, aquilegias have been hit by a deadly new fungal disease; downy mildew. There is currently no treatment, so if you see signs of infection the best advice is to dig up and destroy the plant. See Touchwood Plants for advice on how to spot this. It is with great sadness that we have destroyed many infected plants in our garden, but the good news is that some seem to be surviving, so there is hope that we can continue to enjoy the contribution that these delightful plants make to the spring garden.
A simple single Aquilegia flower - gorgeous. Just keep an eye out for downy mildew.

Anthriscus sylvestris
Ravenswing (cow parsley)

I love ornamental cow parsley, with its dark-purple divided foliage and airy heads of white flowers, for its ability to add height and movement without blocking the view. It likes part shade and will happily insert itself between other plants, often creating a useful background for other flowers. My only complaint is that it sometimes seeds itself right in the middle of another plant and it's the devil to remove without digging up the host. If any seedlings revert to green you should weed them out immediately, unless you want the wildflower look of course. The seedlings are easy to transplant when small. They will survive, but sulk, if kept in a pot, so find them a new home in the ground as soon as possible. Once they have formed seed, gusty wind can set the tall plants off-kilter, but they are easily restored to vertical with a stake.
Two charming self-seeders, the chocolate foliage of Anthriscus sylvestris Ravenswing with the unforgettable dainty flowers of forget-me-not. 

The airy flower heads of Anthriscus sylvestris Ravenswing give this border height without blocking the view of the many low growing Dicentras and other woodland plants. I'm a big fan of tall plants at the front of a border to give depth and intrigue. This border alone has six prolific self-seeders: bluebell, ransom, forget-me-not, cowparsley, foxglove and aquilegia. It requires considerable management, but the slight feeling of wildness that the self-seeders bring is part of what makes it my favourite border. 

Shallow-rooted perennials, biennials and hardy annuals = easy

Myosotis (forget-me-not)
We also inherited forget-me-nots in our garden and I have found them to be a very agreeable companion to almost any other plant. With, and after, the bluebells they add a frothy haze of blue around the garden and are great gap fillers. However, they are incredibly vigorous self-seeders and can easily become too dominant. Life is too short to deadhead forget-me-nots, but the seedlings and plants are very easy to pull out. I cull them regularly while weeding around the garden, making room for other plants to flourish in early spring. When they start to look a little tatty I remove them all, safe in the knowledge that there are plenty more seeds in the ground to take their place.
The humble, but delightful, forget-me-not. 

Digitalis (foxglove)
Foxgloves are mainly biennials; they form a rosette of leaves in their first year of growth, and the following year produce a towering flower spike, much loved by bees for their nectar. They produce vast quantities of seed, but the resulting off-spring may well not look like the parent. They often revert to the pink of the native plant, but sometimes a fabulous new shade is revealed. I find this part of the joy, but I also find that they like to seed themselves in prime, front-of-border positions where they can smother other low-growing edging plants with their large leaves. They resent disturbance, so as soon as you spot a seedling in the wrong place dig it up and move it where you want it to be. They will grow anywhere from full shade to full sun, and seem to blend with any style of planting. I can't imagine the foxglove every going out of fashion.
A lovely peachy-pink self-seeded foxglove.

Lychnis coronaria (rose campion)
Another plant that we inherited in the garden, Lychnis coronaria has become a plant that I would not be without. Its evergreen clumps of silver foliage lift any border in full sun or part shade, and it flowers for months. I find the bright pink variety particularly useful, but having also introduced the white form, they have crossed and given us amazing white flowers with pink centres (sorry, no photo yet). Just one of the joys of self seeders!
Dazzling pink Lychnis coronaria with a low rosette of silver foliage.

Eschscholzia californica (California poppy)
Beautiful, finely divided foliage and a succession of vibrant flowers, the California poppy is remarkably at home in England. I collect seed each year and sow some in the greenhouse just in case, but for several years they have seeded themselves close to the parent plant and my greenhouse seedlings end up in our plant sale when we open the garden for the National Garden Scheme (sadly often overlooked by purchasers because they don't look great in a pot in May!).
Simple, beautiful, vibrant flowers for months.

How could I possibly weed out this California poppy that has made the effort to brighten up our kitchen steps?

Cerinthe major Purpurascens
This hardy annual has interesting glaucous foliage, reminiscent of a sedum, on bushy stems leading to dangling purple flowers. Insects and visitors love it equally. It doesn't seem to care what time of year it is in our garden, so we always have some in flower. It self-seeds close to home, so best to thin out the seedlings so that they don't compete with each other.
A hit with bees and garden visitors, Cerinthe major Purpurascens never seems to stop.

Lunaria annua Chedglow (honesty)
I'm always on the look-out for purple foliage plants, so when I saw the chocolate leaves of this honesty on an Avon Bulbs display I simply had to order a packet of seed. In its first year the leaves remain quite green, but then start to develop dark spots which eventually merge to cover the whole leaf. In its second year it produces lilac flowers, followed by papery seed pods that persist until autumn.
What an amazing colour combination, and one of the few purple-leaved plants I found that likes full sun.
The seed pods of Lunaria annua Chedglow retain their purple tones until they completely dry out.

And for something different - Stylophorum lasiocarpum

Perhaps not for everyone, this plant has striking jagged foliage and yellow, poppy-like flowers. It is happy in shade or part shade, so we planted it on Hellebore Hill and it has now seeded itself everywhere apart from the very sunniest parts of the garden. Amazingly, it looks great everywhere that it has placed itself. Sometimes I think gardening is just refereeing - coincidentally, something that I thought of training to do when I was a student!
Very happy in full shade, the leaves and seed pods of Stylophorum lasiocarpum provide months of interest; the bright yellow flowers are just a bonus.

You can decide whether any of these self-seeders will suit your garden, and your appetite for maintenance. I'm sure there are plenty more to discover, so let me know if you have any to recommend.


Also of interest in the garden at the moment - The yellow tones of autumn have been more striking than the red tones this year in our garden. Lovely when lit by the sun.
Illuminated leaves of Quercus rubra Sunshine (red oak).


Our to-do list

Collecting leaves - I don't mind leaves resting on the border, but I do think the garden looks smarter if the leaves are removed from the lawn. Plus, we wouldn't be without the opportunity to make leaf mould. We have a cylinder of chicken wire that we just tip the collected leaves into. Each year we lift up the wire cage and remove the black gold from the bottom (priceless).

Planting tulips - Tulips are best planted in November and even December. I'm adding to our range of species tulips that stay in the borders all year. We also have several patio pots in which we experiment with colour combinations.

Sowing seeds - Increasingly I am trying to get ahead of myself by sowing more seed in autumn. I will be sowing annual poppies so that I can plant them out early and make more space in the ever cramped greenhouse for spring sowings.

Planning for change - Winter is a great time to plan for changes to the garden. The patio outside the kitchen door has lacked a focus and become a place to store potted plants that were unhappy elsewhere. We are planning to give it a tropical feel (inspired by the print on our lounge curtains!) with hardy palms and dramatic foliage plants. The garden is always evolving.