Hi, welcome to GoY, well Pyracantha would certainly deter intruders, and makes a nice hedge, but be careful which species you buy, as some are not completely hardy, you also need to decide what colour berries you would like, and bear in mind that some species retain their berries longer than others, and as they get larger, be careful when pruning, those spines can be pretty painful, Derek.

Berberis Darwinii would be my choice. Fast-growing, evergreen, spikey, orange flowers and berries. Forfills almost every criteria. Give it a Google but you'll find it will do the job. I found Pyracantha suffered badly from fireblight in my garden.

Native Blackthorn and Hawthrorn grow fast and no one is going to walk through a hedge of it after a few years growth. It is also very cheap as bare root.

I agree with Derek! I planted a pyracantha years ago and have removed it this winter because I just can't face the pruning any more--it was so very spiteful! I suffered some nasty jabs and punctured my shoe during removal but that was the last time it would injure me! Having said that, it had lovely spring bloom and a wonderful crop of red berries which were always popular with the birds so now I need to plant something less aggressive but still providing food for birds.

Botanic gets my vote, they're british natives and beloved by the birds for food and nests
and from the blackthorn you have the making of sloe gin ☺

Botanic gets my vote as well, you could also add some rosa rugosa.

I planted up my hedge at the back of the garden with holly hawthorn blackthorn , rosa rugosa .

The rosa rugosa within a year made a good boundary while the others caught up. They are all finding there own positions and with the holy mix gives it more interest in the winter.

Ours is a field hedge, Gnarly Gnome no holly but the other three with elder in there too, full of birds....

Hawthorn great - also Photinia (red robin) and Copper Beech.

Dont pay for Copper Beech if you have clay soil.

Maybe the clay soil varies Diane? Several of my neighbours have bushy Copper Beech hedges, and we're on alkaline/neutral clay.

If clay/wet soil best to go with hornbean , beech hates wet soil

Gg

I paid for 60 Beech saplings to make a hedge. They all died except 5. Then Monty said on GW that Beech wont grow on clay soil.

Trees are amazing ......some thrive where they shouldn't and die where they should,
we have four fagus sylvatica......the common beech, they're about 5 years old now and growing well we have little topsoil and solid clay below, a friend has a fine sandy very free draining soil who has a healthy common beech hedge.......willow loves wet soil of course.....

I'd go for berberis. Wouldn't touch blackthorn with a bargepole. Round here it sends up suckers yards away friom the parent. It has to be pruned regularly to stop it turning into a small tree and the prunings are the very devil to get rid of. We have lots of it and controlling it is constant.

I wonder if 'we' are trying to deter human intruders or animals??