Wow, dominogold. They should have been able to make it where you live. Before recommending other rhodies that may also fail, I would suggest discussing the environment and conditions where the plants lived.... in order to get a clue as to why they failed to flourish.

You see, PJMs are a very nice looking and exceptionally cold hardy (zone 4) selection... They are heavy bloomers, resistant to some fungal diseases and just very reliable. If PJMs were not surviving in that location, I suggest that we examine what went wrong because something is up.

Your latest plant should be a good starting point... what symptoms did you notice before it died (consider leaf changes, branches, flowers, insect pests); did the landscape company plant them too deep (they should be planted 1/2 to 1" above the surrounding soil); were they root bound (you will have to pull the dead plant out and look); do you think that the landscapers might have disturbed the roots while planting (rhodies have these tiny roots that only grow within the top 4", which is why many people advise not to do gardening projects near the base of these plants); was the soil around the PJMs well draining soil or was it sandy or clayish; do water puddles collect and form where the PJMs were located, etc.; do you know if the soil under them tended to be wet, moist or dry?

Other things that would be nice to know.... how much sun were they getting; can you describe the recommended watering program (how much at the various times of the year, did you use drip?, etc); can you describe any recommended fertilization program (when, how much); any problem areas mentioned in any soil tests done within the last 3-5 years?

Luis

Luis gave you lots of good advice.

PJM's are very easy to grow but there are come conditions that need to be met to grow any rhododendron:

 Soil Drainage: Excellent drainage is important. To test drainage, dig a hole 6 inches deep in the bed and fill it with water. If the water has not drained from the hole in four hours, install drainage tile to carry away excess water, or build raised beds. Moist well-drained soil is a must for most varieties. With poor drainage the leaves will eventually all wilt and fall off.

 Acid Soil: Most varieties require an acidic soil (pH 4.5-6). Powdered sulfur is the best agent to acidify the soil. Holly-tone has this in it. Your plants will get chlorotic (yellow leaves with green veins) if the soil is not acidic enough.

 Fertilizing: More rhododendrons are killed by too much fertilizer than not enough. Chlorosis is yellowing of a leaf between dark green veins. It is caused by malnutrition that can be caused by a wide variety of conditions. They include alkalinity of the soil, potassium deficiency, calcium deficiency, iron deficiency, magnesium deficiency, nitrogen toxicity (usually caused by nitrate fertilizers) or other conditions that damage the roots such as root rot, severe cutting of the roots, root weevils or root death caused by extreme amounts of fertilizer. You don't need to use any fertilizer unless the plant shows signs of malnutrition.

 Shade: Some varieties like full sun to bloom but others suffer from too much sun. Not enough sun will prevent flower buds from forming. To much sun can cause sun scorch on the leaves or may trigger lace bug infestation.

 Mulching: Rhododendrons do best when they have about a 2" to 3" layer of mulch to hold in moisture, prevent weeds, and keep the roots cool. Since most mulches are organic, they need to be topped off periodically, usually about every year or two. Do not make the mulch over 3" thick. Keep the mulch about 2" to 3" back from the trunk/stem of the plants to avoid bark split and rodent damage. Rodents will eat the bark, girdling the trunk and kill the plant.

 Protection: In choosing a location to plant rhododendrons and azaleas, protection is very important. Protect from winter winds. This is especially true when the ground is frozen. Also protect from deer.

 Other Cultural Problems: 1) Cultivating rhododendrons and azaleas must be avoided. They have shallow roots and the roots will be severely damaged by cultivating. 2) Weed killer from weed & feed products is a definite problem also. 3) Salt from sidewalks in the winter is a killer to rhododendrons. 4) Soil near masonry such as foundations and walks is usually alkaline (not acidic) and a problem. 5) Lawn fertilizer in the fall can set a rhododendron way back. 6) Another problem is the roots of walnut trees. They emit a chemical that is toxic to rhododendrons, azaleas and many other kinds of plants.

Here is a link that might be useful: How to grow...