Floating row cover will give you 3 or 4 degrees depending upon its thickness. Check where you bought it from they usually have the rating for it. Upside down pots work. The only thing that won't work is landscape plastic or plastic bags. Frost goes right through that. Cardboard boxes work well also. Last year was bad for late frosts, as you may recall, I used plastic pots over everything that was coming up. Still got some frost damage. Sometimes the cataphyls will give extra protection, but it depends on how far along the pips are. The taller they are, the more likely you will get damaged leaves. Remember that Plantaginea types are more susceptible to late frosts than cold climate types like Sieboldiana. Hope the weather changes for you.

Steve

I don't know what your nighttime temps have been,but I have found that temps as low as 31 will not hurt hostas,at least where I live. When it gets into the upper twenties,them I have problems. I have found that corrugated cardboard boxes offer the best protection,due to the thickness of that type of cardboard. Plastic pots will only protect against frost,as frost has to get on the leaves to damage them. One of the eyes of my montana A. has already been damaged,due to it getting up above the leaves when I wasn't checking it. I go through this every Feb.,as it always starts to come up then. You can't discourage it! Good luck! Hostas start to come up the first of March here,so I have to start checking them then. Phil

Here in Canada's Ottawa Valley well away from the city island of heat, the last frost is generally about May 20 and later is not unheard of. Hostas start to grow when the top foot or so of the soil thaws (frost line is 42 inches, the top foot thaws by April 10th or so) and the pips first emerge by the end of April.

I don't believe in babying hardy plants - the hostas all seem to emerge fine from 5 months or more of dormancy and late frosts seldom bother them. I have seen the pips stand up to being well covered in snow and seem to suffer no ill effects. The leaves fully unfurled in mid May have seen frost (last year for example there was a very late frost around the end of May) without problems.

Early fall frosts are another story. The leaves of most hostas seem to be victimized by our September frosts and quickly brown and fade away soon after.

put them in the garage ..

the cement floor is a great buffer to wild temp changes ... as is a sand floor [my barn] .. anything.. since encapsulated ...

in my blindingly cold z5.. i swear my attached garage is z7 at least ... no wind.. and that heat sink of a cement floor ... [its not that its warm or anything.. its that its constant.. and if it is 3 or 4 degrees warmer than outdoors.. well that would be all you need.. eh???]

the beauty of the garage .. is that they can stay there for a few weeks.. w/o having to cover and uncover.. recover.. etc ...

do NOT leave them covered if sun is expected the next day.. but dont uncover them too early.. most frost/ freeze is immediately just before sunrise..

if you use the garage.. keep the door open during the day.. to keep it cold as possible.. or you will force them even faster ...

all those posts you skipped.. because you thought it would never happen to you.. lol .. what a hoot ..

i wish you luck ...

ken

Well, last year, my favorite, So Sweet, had freeze/frost damage. Of course, that's the two that are further along and in full leaf. I just didn't want the same damage as last year. Always before, I've totally ignored the weather, assuming they are cold weather plants and will do just fine, and usually they do. Maybe Dougald is right, they're tough. I've had some for 15 or 20 years and never covered them. Why start now? Maybe I'll just put the floating row cover on the So Sweets.

bk

Last year's damage

Last year Les could do nothing to protect early emerging hostas because of physical disability. The plantaginea had frozen back three times to the ground. Yet they came back beautifully. I believe in our lovely plants bkay. They have survived possibly longer than we facing all kinds of adversity. i fuss over mine but rarely have they not survived the adversity i fear.
Theresa Ann

I'm not concerned about survival, just looks.

bk

all fragrant .. plantiginea based plants.. are PRONE to frost damage ...

if nothing else.. put those in the garage.. or near the door.. and just bring them indoors at night when temps are to get near say.. 35 ...

your plants are in pots ... i dont understand why you would mess with covers.. etc ...

pips can FREEZE ... once they become active ..... but for the medium in your pot to get that cold.. we would probably be talking about falling toward mid to low 20 one night ... i mean a real FREEZE.. as compared to superficial FROST ...

yes.. they can take winter dormant.. but once they activate.. its another story ...

ken