How to get Agastache through the winter?

Nollie

I’m wondering what people do? Do you mulch over the plants with straw or protect them in any other way? I’ve just cut back the now spent flower stems to discover a lovely cushion of new spring-like growth underneath, which was unexpected...Do I need to protect this new growth somehow from the frosts we are beginning to get? 

Your sage advice welcome as ever!

Perki

I don't cut my agastache black adder to the ground , I leave abit on top to help protect the crown , I then mulch them with leaves. I didn't think they survived last year long cold winter but they came back   

Borderline

You only need to protect the growth if you get really wet weather during the winter time, or have very heavy soil. What tends to happen is, the growth will slow right down and may go a bit yellow and die back a bit, but come spring time, they soon start growing again.

AnniD

I have some agastache "Sangria" that l grew from seed. They are still flowering but starting to look a bit yellow leaved and tatty. I have noticed the cushions too. Is it worth just cutting them back to tidy them up as they're right outside the window, or would it make no odds and l should just cut them right back. They are on well drained soil.

Nollie

Oh I’m glad yours survived, @Perki , that gives me hope!

@Borderline yes to both cold wet winters and heavy clay soil as well as serious frosts. I did mix in a generous amount of grit and compost into the whole bed and added more grit to the planting holes, though.

I wondered if they might rot if I covered them in anything like leaves or straw, which would get wet and claggy...but better to cover than not would be the consensus? 

Borderline

I don't recommend covering with stuff like straw. You're more likely to cause excess damp when rain comes because it will not really drain away quick enough, but linger around.

If you are very worried, if you can, dig slightly below soil level around the base of your clump and add a layer of gravel around its neck area. I do this will my Alpine plants that tend to resent dampness around the base. Chipped bark mulch is also good around the base. Helps to keep the top inch free draining and drier.

Paul B3

Would it be possible to lift them and overwinter in a cold-frame or unheated g/house ?

Nollie

Oh, thank you Borderline, I will do that - the Black Adder I planted on a slight mound so it will be easy to give them a collar of gravel, the Aurantica type in another new bed have sort of sunk a bit and are probably in too rich a soil, so would benefit from more grit/gravel, I think. 

The tattiness factor is why I chopped mine back, AnniD - the perils of being a neat freak!

Kitty 2

I didn't know agastache needed winter protection.
I have a pot of 'Golden Jubilee' that I grew from seed in 2017, it was chopped down after flowering and left out in all weathers last winter. Survived and came back even bigger this summer. Maybe I was lucky?

AnniD

Problem with lifting them Paul, is that my coldframes are stuffed as it is. After posting l had a look through my seed packets and l have some seeds left, so if they don't make it, l will have another go ! 

Nollie

I’ve decided to work to the principle. Paul, that if a plant doesn’t survive my winters in the ground (with as much help as I can give it) then either it goes, to be replaced with something hardier or If I really love it, to grow it as an annual. It’s their first winter, so it’s a case of wait and see..