Laura Bilodeau Overdeck is founder and president of Bedtime Math Foundation. Her goal is to make math as playful for kids as it was for her when she was a child. Her mom had Laura baking before she could walk, and her dad had her using power tools at a very unsafe age, measuring lengths, widths and angles in the process. Armed with this early love of numbers, Laura went on to get a BA in astrophysics from Princeton University, and an MBA from the Wharton School of Business; she continues to star-gaze today. Laura’s other interests include her three lively children, chocolate, extreme vehicles, and Lego Mindstorms. Our gardens are under constant threat of invasion. The enemy? Several common British perennial weeds (not to mention the annuals we’ll see in a later article). As these are perennial, they have the nasty habit of hanging around whatever happens. It also renders their removal more difficult.
When You Wish Upon a Fluff
You know those cute yellow flowers you see in the grass? Or have you seen round, white poofs of fluff that you can blow into the air to make a wish? Those two flowers are the same flower. They’re called “dandelions,” which comes from the French words for “lion’s tooth.” They’re bright and friendly-looking, but grown-ups can’t stand them. Dandelions are weeds, meaning they suck up more than their share of water and vitamins from the dirt. That makes it harder for grass to grow. But until the 1800s, people used to grow dandelions on purpose. We can eat any part of the flower — the leaves taste pretty good in a salad! Luckily for us, each flower holds up to 400 seeds, which can sail as far as 5 miles. Dandelions are here to stay.
Wee ones: If you have 7 yellow dandelions and 4 white fluffy dandelions, of which kind do you have more?
Little kids: If 1 dandelion seed sails 5 miles in one direction, and another seed flies 5 miles in the opposite direction, what’s the farthest apart they can land? Bonus: If each time you blow on a dandelion you blow 5 seeds free, how many wishes does it take to blow 20 seeds away? Count up by 5s!
Big kids: Dandelions can have up to 400 seeds, but they usually have around 180. How many more seeds does a mega-fluffy 400-seed dandelion have than the usual? Bonus: If you blow off 300 seeds, and each of those makes a new flower that sends off 300 seeds, how many seeds sail off in that 2nd round? (Hint if needed: what if each of the 300 sent off just 3 seeds…then what if each sent off 30 seeds instead…then how about 300?)
Wee ones: More yellow dandelions.
Little kids: 10 miles apart. Bonus: 4 wishes: 5, 10, 15, 20.
Common British perennial weeds
Our gardens are under constant threat of invasion. The enemy? Several common British perennial weeds (not to mention the annuals we’ll see in a later article). As these are perennial, they have the nasty habit of hanging around whatever happens. It also renders their removal more difficult.
How to deal with these common British perennial weeds
Organically, the only real eradication method is digging out as much of these plants as possible. They often root deeply or spread widely, so this is no mean feat. If they’re rhizomatous – a rhizome being an underground spreading stem – it’s important to dig out as much of these rhizomes as you can. If they have deep tap roots, they can regenerate from its top part, so we must take out as long a segment of this as able.
Regular hoeing or cutting back of regrowth will significantly weaken the plants over time, but cannot guarantee complete removal. Similarly, you can weaken them by covering the flower bed with thick black polythene. Your prized plants must be carefully removed first however, ensuring no weed roots coming out with them. You’ll also have to leave the polythene in place for much of a year at least, to ensure effectiveness.
If you’re gardening in an eco-friendly way, persistence and patience are key.
If you’re happy to use chemical controls, then this RHS list shows you the range available. Each RHS profile for these perennial weeds will tell you how to chemically eradicate them in more detail. Links can be followed by simply clicking on the weed’s common name.
Latin name: Rubus fruticosis agg.
Other common names: Blackberry
Insight: Stems can grow up to 2m in length and root when the tip touches the ground.
By Rasbak – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=170853 CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=331505
Latin name: Elymus repens
Other common names: Scutch grass, twitch grass
Insight: Spreading rhizomes which can tangle around the roots of other plants, making removal trickier.
Latin name: Ranunculus repens
Insight: Runners develop from each leaf node, each forming a strong root network when touching the ground. Seeds and severed nodes also aid its spread.
By Isidre blanc – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=37282015 By No machine-readable author provided. Rita~commonswiki assumed (based on copyright claims). – No machine-readable source provided. Own work assumed (based on copyright claims)., CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=953061
Latin name: Cirsium arvense
Insight: It has a deep tap root as well as many seeds carried on the wind. Its roots also spread out and are brittle, meaning any snapped off during extraction can re-shoot easily.
CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=134740 By Andreas Trepte – Own work, CC BY-SA 2.5, https://commons.wikimedia.org/w/index.php?curid=1989689
Latin name: Taraxacum officinale
Insight: We’re all familiar with its fluffy seed heads that fly around between March and October. It also possesses a deep tap root from which it can regenerate.
By Rasbak – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=374147 By H. Zell – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=11040278
Latin name: either Rumex obtusifolius or R. crispus
Insight: It has a branching, thick tap root delving up to 90cm deep. Its seeds can survive in the soil for up to 50 years. Digging out at least the top 12-15cm of the tap root should however prevent the individual weed’s regrowth.
By Franz Xaver – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=8024702 By Drahkrub. Attribution must include the URL http://de.wikipedia.org/wiki/Benutzer:Drahkrub. – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=36561552
Latin name: Aegopodium podagraria
Other common names: Gout weed, bishop weed, jump-about
Insight: Another troublemaker that creeps via its rhizomes, needing careful digging out
Latin name: Calystegia sepium
Other common names: Bellbind
Insight: Its white trumpet-like flowers are pretty, but this is a major pest. Its rhizomes can spread up to 2m a year and the smallest segment of rhizome will regrow.
By de:User:Jutta234 – self taken foto, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=2814457
Latin name: Equisetum arvense
Other common names: Mare’s tail
Insight: Easily recognisable as it resembles miniature pine forests. It’s the opposite of hedge bindweed, sending its roots up to 2m down into the earth. Its rhizomes spread quickly and up spring dense clumps of foliage.
By User:Gerhard Elsner – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=1747136
Latin name: Hedera helix
Insight: This is invaluable to wildlife and has some uses, but it can smother both horizontal and vertical surfaces if uncontrolled. It’s self-clinging, and when creeping over the ground, it can root at frequent intervals.
By Rasbak from nl, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=1762582 CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=883223
Latin name: Urtica dioica
Insight: We all know these varmints from their sting. The roots creep under the surface and can send up shoots reaching a maximum of 1.2m in height.
Latin name: Chamaenerion angustifolium
Other common names: Fireweed
Insight: This plant has attractive pink spires up to 1.5m tall; a white cultivar is available for the larger garden. As a weed, however, its fluffy seeds can fly around on the breeze. Again, its rhizomes spread too, although fortunately it roots shallowly.