Seeing the plant creature's attention focused on Lizzy as both Tex and the steel defender retreat, Rel also moves thirty feet west down the hallway towards the western door.  She tries to leave room for her allies to move around and past her.

Turning, she sends another jet black beam of energy at the aggressive aberrant flora, trying to blast it backwards.  Only realizing too late that she might be sending it back in Lana's direction.  "Look out," she shouts to the ranger belatedly.

Zane smiles quietly as he sees the plan working.

He stage-whispers the next insult (vicious mockery) at it, "I've seen more intimidating flora in a hanging basket!" for 3 damage.

He move back another 15 feet and takes a quick glance around to see if anyone else has finally noticed all the fighting.

EOT

Bellamy takes the disengage action and moves far to the east to to give him some space.

End of Turn

Lana clicked her tongue, she did not think straight and ended up on the wrong side of the monster. Nevermind. The animated hip of grass proved to be vulnerable, and Lana continued to shoot.

Crossbow: Attack: 27 Damage: 10 (piercing) + 1 (HM, piercing) + 3 (psychic)

EoT

Updated Bellamy's Turn

1. Bellamy moves west 30 ft.

2. Then cast magic missile at the plant monster.

14 force damage

EOT

The plant monster rushes towards its closest target, as it is falling apart. Smashing down with terrible accuracy at Lana. Missing with each strike.

Tex rushes forward to assist Lana, and attacks with his spear as soon as he is in range. Lizzy is too far away but moves as far as Tex and initiates a repair programme.

Zane gets close enough to insult the monster again, "You're nothing more than fertilizer waiting to happen!" (vicious mockery) for 2 damage.

EOT

1. Bellamy cast magic missle again at the creature

9 force damage

End of Turn

Rel stays where she is and joins the barrage to finish of the aggressive vegetation:

Eldritch Blast to hit:  20
Eldritch Blast damage:  10 (force)
Repelling Blast:  target pushed 10' back (east)
No movement.

EOT

"Phew, that was close!" Lana stood over the hip of rotting vegetation looking at it more with surprise than disgust. "Had some idea when I ran to the other direction but gods know what it was. Oh, well." She crouched near it and pocked a few times with the sword. "Anything useful inside?" (Perception: 13, Investigation: 7) "Anyway, want to check out the garden now when we killed the guardian?"

In case anyone indeed wanted to check it out, she curiously (and cautiously too) stepped inside. (If another Perception is needed: 22)

(if the combat is over)

Zane says, "I'll keep watch."

And he will be just inside (corridor side) of the doors to the main hallway (with stairs) and ritually cast silence at the top of it where it seems like doors might be.

While Zane casts silence, Tex uses the time to refresh his own spell of Detect Magic with a ritual but wisely at a  safe distance from Zane. “Too many traps here… No wonder they don’t have guards, they don’t need them. We could be dead three times over.” 

A few of you unleash fury upon this rotting heap, and then watch as it falls into a wet slop of weeds on the floor, unmoving. The plant creature does not contain anything useful upon inspection. With the threat dealt with, Lana takes a peak into the greenhouse. 

Lana

 Tex

"Whew I am glad that plant beast is done for. Lana is there anything else in the greenhouse?" asks Bellamy

Tex joins Lana in the greenhouse and, before entering, peeks towards the end of the long corridor to see how or if it  continues. In the greenhouse he checks for any sources of magic. Meanwhile he comments, “I’m beginning to believe that we should move on, or better down into the cavern. This mansion starts to look like a distraction to me, I see no reason why someone puts all these things here if they are to stay. This exploration draws out our resources. True we might find something useful or valuable but it is costly. We’ll need our energy if we are to face that female.”

Rel blows her breath out upwards through her lips in frustration, causing her silver hair to flutter slightly.

"Yes.  I am sorry I pushed to explore the entire greenhouse.  I still lean towards checking up the stairs so we cover our back, just in case.  And possibly find further clues or even the coffin.  But I will go with what the group decides of course."

Tex, the hallway does not lead further from what you can tell. There is a wall at the end of it.