You can make the led string, however long you like and with as many leaves as you want.

What you need:

• Some wire
• 2 stranded cable
• Some yellow and red LEDs
• Some 50Ω resistors
• Battery holder for 2 AA or AAA batteries
• 3d printed leaves
• Heat shrink tubing or electrical tape

Printing:
There are three different leaves which all can be printed on their flat base without support. You should print it with translucent filament, often sold under the color natural. I printed it with perimeters only.

How to put it together:

The Electronics are very simple:

You have your batteries outputting three volts with a switch. There are three LEDs per light. These are soldered together in parallel with a 50Ω resistor in front. All the led groups are soldered in parallel.

Assembly:

Soldering the LEDs:
This can be quite tricky, but I'll show you the way I found works the best.
First lay out the resistor and a piece of bare wire in front of you like shown in the image.

Lay the LED on the wire and the resistor and solder it to them.

Repeat the process with all three LEDs. It should be noted that you can use any combination of red and yellow and it looks best if you vary the combination for every leaf.

Cut off the excess wire from the LEDs and insulate the wires.

After soldering the amount of LED groups as you want leaves solder the LEDs to a length of cable you want with the distance you want in between.

The last step is glueing the leaves to the leds with hot glue.