slowing down

The dramatic lifecycle of horse chestnut trees - and their close relatives the buckeye - makes a great hands on nature table study for kids that they can track across the seasons in a simple nature journal.

The grand scale of chestnut and buckeye buds, flowers and protected nuts provides children with a handy framework for observing reproduction in other tree species Darwin style.

This post gives you a visual guide to each stage in the chestnut and buckeye lifecycle plus tips on what to look for and explanations of what's happening.

The nature study is simple enough to enjoy with pre-school and kindergarten children but also provides a strong foundation for studying tree life cycles and reproduction with older kids through into middle school.

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Table of Contents

Horse Chestnut Tree Buds

Horse chestnut trees are loved by children for their conker brown nuts but are actually up to all sorts of clever stuff throughout the year and provide a wonderful opportunity for children to observe close up the lifecycle of trees.

The horse chestnut trees are one of the first trees in bud in late autumn and early winter. And boy, their buds are big!

PLUS they're sticky.

Give them a feel and you'll get gluey resin on your hands. They need to be sticky because they are so big.

Look up closer and you'll see the gluey stuff seems to be holding separate plates together. The plates and glue let the bud grow much bigger without popping open.

Opening Chestnut Buds

As the sun shines and air warms in early spring, the gluey stuff melts and the plates fall back.

And when the buds start opening, you realise why they needed to be so big.

Inside the bud are both the already large leaves and the structure of the distinctive flower.

That clever sticky stuff on the bud not only gave these space to grow but also provided a water proof coating against the rain. How clever is that?

Horse Chestnut Blossom

But the horse chestnut tree has lots of other clever tricks up its sleeve.

When the blossom emerges - in April in our lovely local London park - from the individual buds on the flower structure, it's white but yellow in the middle.

Now as you know, horse chestnut trees are big fellas. So there's an awful lot of blossom the tree wants pollinated by the friendly bees.

To help that happen, the horse chestnut blossom centre turns from yellow to pink once pollinated, so the bees and all their friends don't waste time on already pollinated flowers. Smart stuff!

(Check out my See Like A Bee Nature Hunt to learn why bees can't see pink!)

Chestnut Pollination

May is the traditional time in the UK and especially London for horse chestnut festivals. This is when the blossom is at its most magnificent with big flowering candles all over the tree.

But if you look closely, you'll see the bees have already done their work. And there are oh so delicate, little conkers growing in the blossom.

These tiny beauties are lovely on a nature table. And make a beautiful prompt for nature journal sketches and paintings including simple petal paintings and collages.

Leaf Energy For Growth

The tree's enormous green leaves will over the summer convert the sun's energy - via photosynthesis - into the fuel that tiny seed needs to become a full grown conker.

If you want to include leaf drawings or rubbings in your journal, it's best to do them early summer as the leaves deteriorate quickly as the conkers grow.

Horse Chestnut Shells & Prickles

Tiny horse chestnut and buckeye nuts are supported from the very start of their long 4 month growth cycle by tough - and for conkers prickly - shells. The shells keep out obvious predators like squirrels but also in surprising ways protect the nuts from weather and parasites as they grow.

Moisturising & Cooling

The horse chestnut at this stage - over the summer - is creamy white and soft inside. Unlike most nuts it is a "wet" seed high in starch and water not oil. The thick fleshy husks of the chestnut and buckeye keep rain out but also keep their seeds moist.

The horse chestnut shell also keeps its seed cool in the hot sun by performing transpiration. Moisture evaporates through tiny pores for a cooling effect.

Parasite Protection

Big moist nuts that take a long time to grow are vulnerable to all sorts of fungi, bacteria and bugs. The thick conker and buckeye shells keep these out.

But the white nuts are also rich in saponins and especially aescin that can defend against bacterial and fungal attacks. These saponins foam in water and are what allows chestnuts to be used as laundry soap!

Final Growth Spurt

At the end of summer conkers put on a final growth spurt and this is when their green chlorophyll rich shells come up with another awesome trick.

The tree's big leaves are tired and drying out by this point, so the green conker shells actually perform photosynthesis themselves and directly feed sugars to the starchy seed.

Keep inspecting the conkers and buckeyes near you as they are growing through the summer. Pick them at different sizes and cut them open - carefully - to inspect the nut and the inside of those amazing shells.

Ripe Horse Chestnuts

Finally in late summer to early autumn, the conker or buckeye is big enough to start producing a tree.

That creamy centre has two fully grown Cotyledon energy "batteries" that will give the baby tree the energy it needs to start growing before it has any leaves and can get energy from photosynthesis.

This is the point the distinctive glossy dark brown coat - the testa - finally appears. It is an oily, waxy waterproof barrier that locks moisture inside the creamy seed so it doesn't dry out over winter and keeps out damp and fungi.

The big outer shells now weaken their defences so when the conker or buckeye falls they break open and the nut pops out ready to grow into a tree.

Growing A Chestnut Tree

As the glossy brown conkers and buckeyes tumble out of their shells, squirrels actually help out.

They eat quite a few as they are a great source of fat and protein for squirrels. But they're pretty filling snacks so squirrel will scurry off with plenty of them and bury them around the place.

Forgotten hoards of nuts emerge as new conker and buckeye saplings.

So be like squirrel and collect a hoard of shiny nuts - for conker games & activities - but also bury some in a pot and leave them out over winter.

Oddly, the new conkers and buckeyes do nothing for the first 2-3 months of late fall and winter cold. They may look dead, they are not! After all of that long summer growth they hibernate until spring comes around again because it is too cold for them to grow.

In early spring you will see the first signs of germination and in late spring your new horse chestnut or buckeye sapling will actually appear.