Intense Flowering of the Sandpaper Vine (Petrea Volubilis)

For a few days now, I've noticed that my Sandpaper Vine (Petrea volubilis) also known as Queen's Wreath has been flowering more than usual. I've had this vine for five years now and have taken interest especially on the vine's first flowering three years ago. It is only now that neighbors even took notice on the masses of flowers bloomed. Some passersby inquired on how it has flowered this way.

Possible Reasons for the Prolific Blooms

I, myself, was pleasantly surprised and so tried to analyze what recent actions I made or developments that occurred recently. Certainly, I'd like to replicate this prolific blooming every time the vine flowers.

1. Drop in Temperature
   
   We've had extraordinarily cold mornings in the past few weeks. The coldest so far this year was 18 degrees Centigrade and this occurred at 5 to 6 am in the morning.
   
   Yes, 18 degrees Centigrade is already cold in my country, the Philippines. During the hot season which runs from March to May, we could get temperatures from 34 to 38 degrees Centigrade.
   
   Our hardiness zone is Zone 14. From what I've read, the Queen's Wreath thrives for areas in Zone 10 and above. Maybe the drop in temperature especially in the mornings stressed the plant enough to promote such intense flowering.
   
   
   
   
   
   
   
2. Pruning Large Branches
   
   I pruned many big branches of the Sandpaper Vine or Petrea volubilis. Did the pruning of the large branches induce the flowering? I don't know for sure, but I did this for two reasons:
   
   
   • Branches on the main trunk did not have many flowers.
     
     Originally, I had planned on having a tree-like shape and form for the vine. As it grew, I religiously pruned side branches, ensuring there would be a single trunk for the sandpaper vine.
     
     To achieve the tree-like structure, I also straightened the vine's trunk when it bent. This needed to be done while the trunk was still young and thin. The main trunk now is 4 centimeters in diameter and virtually impossible to bend or train.
     
     Eventually, it did flower, but not as much as I expected. The flowering really took off, however, once the branches reached the garden arbor or pergola that was fabricated. So I cut off the other branches on the main trunk but left those that are on the garden arbor.
     
     
   • Branches on the main trunk kept climbing the guy wire.
     
     This is probably the bigger reason. You'll notice there's a guy wire behind the vine. This guy wire connects from the ground to a street light post. Even with a homemade vine guard installed, the vine's branches still manage to twine on it and climb the guy wire. It is always a pain to cut and remove the vine branches that have climbed up the guy wire.
     
     
   
   Shown below are before-and-after photos. The "before" photo was taken 3 years ago when the Sandpaper Vine (Queen's Wreath) first started flowering. Notice how the vine's trunk is much thicker now.
   
   
   
   Again, maybe the heavy pruning stressed the vine enough to induce more flowering.
   
   
3. Age of the Sandpaper Vine
   
   The vine, after all, is already five years old. Just to visualize how old it is, shown below is the vine's main trunk. The main trunk is 4 centimeters in diameter, and bigger at the base.
   
   
   
   It's mature, very stable, and so needs little maintenance. I guess, it would be a consistent bloomer, regardless.
   

Care and Feeding of the Sandpaper Vine (Petrea volubilis)

1. Fertilizers to Apply on the Sandpaper Vine
   
   Some have asked what fertilizers I put in it. As far as fertilizers go, I put nothing nowadays. During its growing stage which was just the first two years, I did occasionally apply complete (14-14-14) fertilizer to promote flowering in the Sandpaper Vine. Occasionally means probably just once every two months.
   
   
   
   
   
   
   
2. Watering Needs for the Sandpaper Vine
   
   Regardless of weather (dry or rainy season), I presently water it once a day. Now that the vine is much bigger and mature, I could water it with a small basin-full of dishwater. That's right. I wash the dishes and after that I simply pour the leftover dishwashing water on the vine's base on the ground. There's really nothing more.
   
   
3. Need for Sunlight
   
   The vine gets four hours of direct sunlight, on the average. It's mostly under the shade of the house in the morning and gets sunlight in the afternoon. The vine branches that have grown on the garden arbor get the most direct sunlight. The vine itself is planted in the ground.
   

Other than these observations, I've not noticed or done anything else. There was a recent volcanic ash fall from Taal Volcano, but I doubt if that had anything to do with the profuse blooms.

So, that's essentially what I have to share to hopefully explain the reason for the intense flowering of the Sandpaper Vine.