Question:  Can I plant my hibiscus plant in zone 4?  What special things do I need to do to it to keep it looking nice. 
Answer:  You don't say what exact hibiscus you have, but assuming you bought it locally, it is very likely hardy in your zone.  Hibiscus is a wonderful, practically care-free plant that will reward you with big but delicate-looking colorful blooms from late summer to the first killing frost.  It grows in full sun to part shade, and most varieties will get big - 4-6 feet - so plan for that.  The only problem you might encounter is the actual move into the garden.  Hibiscus is very sensitive to root disturbances and if you are going to kill this plant, this is where it will happen.  Make sure you have dug a generous hole that will accommodate the plant easily at the same depth it was in the container.  Gently remove the plant from the container, and don't tease the roots as you would other plants, but rather just gently set the plant in the hole, scoop the soil back in around it, and carefully tamp down.  Water in well then and keep moist for a few weeks thereafter.  Mulching is a must with this plant, both to keep down weeds (it even resents weeding around its roots), and to help it survive the winter.  As far as maintenance otherwise, there basically is none.  The plant dies down to the ground in winter and springs forth late (so be patient in spring - it might be June before you see it again).  No pruning is necessary or recommended as flowers are borne on the new wood.  Of course, if one branch gets out of line, you can certainly prune that to keep the shape, but any heavier pruning will destroy valuable flower buds.  Water during the growing season as necessary and enjoy!  You have chosen a rewarding garden statement for your landscape that you will enjoy for years to come!

Question:  I purchased a hibiscus tree and impatiens and they both seem to be slowly dying...  the hibiscus is turning yellow and the impatiens are becoming sticks...  what am I doing wrong?
Answer:  You don't say where you are, but my gut instinct tells me too much sun for both.  Hibiscus is a sensitive plant, especially at first - refer to the answer above for specifics.  If you are in the south where the hot season lasts for a long time, and you have your Hibiscus in full sun, it's probably too much.  Some afternoon shade would be very beneficial.  Leaf yellowing is a common problem with all Hibiscus plants at various points in time and can be caused by any change in temperature, humidity, and of course, transplanting.   The good news is that the plant usually recovers quickly once it gets over the initial shock, whatever it was.  As far as the Impatiens, I think they are getting too much sun too.  Impatiens are great plants except for one thing - they will wilt down to sticks within hours if they get too much sun and not enough water.  In my zone 7 garden, where I have good soil and plenty of shade, I still find myself watering the impatiens almost daily.  They will look great at 7 in the morning and by noon they are all shriveled up.  The revive pretty well with watering but obviously it will compromise their overall health if you let this go on daily.  Hopefully your solution will be to just adjust whatever needs adjusting to keep these plants healthy and happy, and by all means, mulch both to help keep soil moisture even so that you won't have to kill yourself watering every half day!

Question:  I have a white fuzz on my Hibiscus and another plant in my front yard.  It looks like a roly poly covered in white fuzz. 
Answer:  Sounds like mealybugs.  Mealybugs suck juices out of their plant hosts and cause stunting and disfigurement.  You don't say how extensively you see these on your plants, but if the plant is covered with them you will probably have to pull it up by the roots and dispose of it in a tightly sealed plastic garbage bag. You definitely don't want this bad boy to spread any more than it already has.  If you just see a few, you can try pruning out branches that are more heavily infested and dabbing rubbing alcohol on isolated individuals elsewhere with a Q-tip.  Also, a strong spray of water to dislodge as many as possible and reduce the population is a good idea, as is a good bath periodically with an insecticidal soap to help keep re-infestation from occurring.  Insecticides don't work very well on mealybugs because they have tough outer protection.  Good luck!